Bayern Munich made it three wins from three in the Champions League but some familiar failings made it tough going. A Robert Lewandowski brace and a great Corentin Tolisso strike proved just enough against Olympiacos.
Olympiacos 2 - 3 Bayern Munich
(El Arabi 23', Guilherme 79' - Lewandowski 34', 62', Tolisso 75')
Bayern showed the same lack of punch that has haunted them domestically in recent weeks, but, once again, their number nine papered over the cracks.
Olympiacos frustrated their opponents early on and took their first real chance. With two disciplined lines to keep Bayern at bay, the home side turned the ball over, switched the play, flung in the cross from the left and Youseff El-Arabi's header was confirmed to have crossed the line by goal-line technology despite Manuel Neuer's best efforts.
Bayern's central defensive pairing of Benjamin Pavard and Lucas Hernandez were unconvincing in their defensive duties and slow in their build-up. Pavard was fortunate not to score an own goal, with a cross deflecting off him into Neuer's grateful arms.
As has been the case in recent weeks, Bayern were bailed out by the ridiculously in-form Robert Lewandowski. The Polish headed down for Thomas Müller, and after the German's shot was parried, Lewandowski drilled home the rebound to equalize before the break.
The hour mark came and went and it was still Olympiacos who looked the more dangerous. Philippe Coutinho, who missed a good chance, was ineffective along with Thomas Müller. Worse still for Bayern was that Lucas Hernandez was lost to injury, plunging Kovac into an even greater defensive crisis.
Lewandowski came to Bayern's rescue once again. Olympiacos failed to clear a corner, the striker just got a touch on the ball before the on-rushing keeper and the ball dribbled over the line. After a quick check with the VAR, the goal was given, Bayern were ahead. Lewandowski took his season tally to 18.
Bayern's nerves were calmed thanks to a superb third from substitute Corentin Tolisso, but only four minutes later Thiago's outstretched arm deflected Guilherme's long-range effort past Neuer and the game was a contest again.
The visitors survived a nervy finale in which Olympiacos might have found an equalizer had Daniel Podence been more accurate in the box. The result secures Bayern their third straight win in Europe this season and stay top in control of Group B.
As it happened
FULL TIME: The corner is overhit and the whistle is blown. Bayern hang on, just about. This one was far from comfortable.
90+4 - Corner to Olympiacos, seconds left...
90+3 - The excellent Podence, now popping up on the left, does brilliantly to make some space and set up Lovera just outside the box. But Boateng gets a block in. Coutinho then gets a sight at goal at the other end but he takes a touch and his shot is also blocked. Frantic stuff.
90+1 - The corner is overhit and Alaba clears easily.
90' - Neuer does well this time to judge a long ball and catch it just inside his area. El Arabi has been booked for something, which I imagine is related to the rebound a minute ago. Olympiacos have a corner and we have four minutes of injury time.
88' - Late chance!
A lovely move almost brings an equalizer. El Arabi carries the ball upfield before finding Podence. He drifts away from Boateng, ducks in to the area from the right and hits a firm drive. It's straight at Neuer but he briefly spills it, recovering before El Arabi can pounce. The Bayern players react badly to the striker going for the rebound but he had every right to. Neuer got away with one.
86' - Gnabry and Coutinho try and find a way through until the former's cross is blocked out for a cornerm which is easily cleared. Kovac brings on Perisic for Müller and the hosts make their last change.
84' - Thiago lofts in a cute little ball to Kimmich 12 yards out. It's a difficult one to get over and the rightback loops it in to the keeper's arms.
83' - Podence gives away the ball under little pressure in midfield, not what the hosts wanted. The crowd believe now but can Olympiacos put this creaky Bayern defense under enough pressure?
79' - GOAL! Olympiacos 2 - 3 Bayern Munich (Guilherme)
They're back in it. The Brazilian didn't have much on so took a pot shot from 30 yards. Thiago dived in to block and the ball struck the Spaniard on the arm to elude Neuer. A nervy 10 minutes could well await now for Bayern.
78' - Müller tries to get in on the act with a 12-yard snapshot on the bounce from Gnabry's shot but he can't keep it down.
75' - GOAL! Olympiacos 1 - 3 Bayern Munich (Tolisso)
Müller hunts down and wins a ball then, after some smart link up with Alaba, Coutinho tries one from 10 yards. It deflects out to Tolisso who takes his time and curls one beautifully in to the top left corner from 20 yards. Great strike and the Frenchman's first goal for more than a year.
73' - Substitute Lovera takes this corner and Lewandowski clears. This one is still alive. Semedo the latest to see yellow after taking out Thiago.
72' - Podence is on the deck and Neuer is sprinting over to make a point. It seems Kimmich thought Olympiacos had played the corner and Podence tried to block him from playing the ball. Neuer is booked and Bayern can only clear the resulting freekick for another corner.
71' - Podence is causing real problems on the right. He, once again gets space and tries to clip in a ball to El Arabi but Pavard is across well to clear for a corner.
70' - A free flowing move from Bayern, a rarity tonight, is ended when Jose Sa is out quickly to beat Müller to a cross from the right.
68' - The hosts make their first change. Lovera is on for Bouchalakis.
66' - A little bit of air has gone out the game, as you'd expect. Have Olympiacos got it in them to get up a head of staem again?
62' - Olympiacos 1 - 2 Bayern Munich (Lewandowski)
The home side can't clear a corner, Müller seems to get something on it and Lewandowski, of course, reacts fastest to poke it home. There's a quick check for offside but he's ok. Harsh on the hosts and where would Bayern be without their number 9?
59' - Hernandez can't continue, another defensive injury for Bayern and the French defender looked in some pain after he was caught in a strong challenge. Boateng is on to replace him.
56' - Podence again skips easily down the right and lifts one deep to the back post. Kimmich gets his body the right side of his man though and danger is finally averted. Hernandez is currently off the pitch receiving treatment.
54' - Kimmich cuts in from the right but can't find a shooting angle. He then tries to lay the ball off but no teammate is alive to it. And now Hernandez is down clutching his leg...
52' - Some smart play down the left from the hosts is ended when Alaba hacks out Bouchalakis' cross for a corner, which comes to nothing. The hosts have bossed this half so far.
50' - The crowd are sensing their side are in with a chance as Guilherme controrts his body to try and turn a corner goalwards, to no avail. It's all Olympiacos so far and Thiago goes in the book for a late, and frustrated, challenge.
47' - Chances for the home side!
Podence dances round a cluster of Bayern players without any going to bother him. He dinks a cross towards Masouras, who is equally untroubled but floats a header wide. Moments later Meriah is inches away from getting on the end of a deep freekick at the back post. Shocking start from Bayern.
46' - We're off again. Bayern have made a change at the break, bringing on Tolisso for Martinez. The Spaniard didn't appear to be injured.
HALF TIME: It ends all square at the break. The German side have had the better of it but, one big Coutinho miss aside, haven't created all that much. They've looked vulnerable on the few occasions they've been asked to defend and paid the price in the 23rd minute when Youssef El-Arabi headed in at the back post. But Robert Lewandowski gobbled up a rebound to level things up.
44' - It's fair to say Bayern are looking fairly comfortable but also that they look shaky when asked to defend.
41' - We've just seen a replay of the opener, given by the video review system. It can't have been more than two millimeters over the line. Fine margins.
39' Big miss!
What's happened here? Lewandowski pulls wide to slip in Alaba. He drives in a low cross from the byline on the left and Coutinho has got ahead of his man. He's three yards out but somehow blazes it over. He was under pressure but that is a bad miss.
37' - Gnabry has switched wings and tries to chop in from the right but it's not quite happening for him yet and he's tackled before handballing.
34' - GOAL! - Olympiacos 1 - 1 Bayern Munich (Lewandowski)
Who else? Martinez pumps in a cross and Lewandowski rises to nod it in to Müller's path. The German strikes an acrobatic effort well and Jose Sa can only palm it out. The poacher supreme does his thing with a deceptively good finish from the rebound. He's scored in 12 successive games for Bayern.
31' - Chance for Olympiacos!
Almost two. Again the Greek side get in down the left. Tsimikas receives it on the overlap and whips in a dangerous low ball. Pavard throws out a leg to try and clear but directs it at his own goal. Luckily for him it's right in Neuer's midriff.
30' - A brilliant ball from Thiago gets Kimmich to the byline. He slides as he crosses it in but it's cleared at the front post. It's a similar story from the corner.
28' - Lewandowski slips in Gnabry on the left corner of the box. He opts to shoot and it's blocked, looping harmlessly in to the keeper's arms. Lewandowski throws up his arms in frustration.
26' - Pretty dreadful defending all round from Bayern there and the hosts score with their first meaningful attack. They'll surely be even happier to sit back now. What have Bayern got?
23' - GOAL! Olympiacos 1 - 0 Bayern Munich (El Arabi)
Out of nowhere the hosts lead. Tsimikas skips away from Müller who went to ground easily on Bayern's right and picks out a lovely whipped cross to the lone striker at the back post. El Arabi gets up above Hernandez and heads downwards. Neuer, whose positioning didn't look great, tries to shovel it out but it had crossed the line.
22 - Coutinho shows lovely feet to evade his man and slip it to Gnabry on the edge of the box. But for once the winger can't make it count and it's nicked off his toe.
21' - Bit of news from the other game in this group where Spurs already lead 2-0. The goals have come from Harry Kane and Son Heung-min.
19' - Martinez tries a pass from the center out toward Müller 30 yards away on the right. It's a Row Z job. Dreadful.
16' - Müller clips in a decent cross from the right. It's cleared as far as Lewandowski who can't quite get it out of his feet and floats a harmless effort over the bar from the edge of the box.
15' - The hosts are barely getting a kick and don't seem interested in closing down their opponents until the final third. A dangerous game.
13' - Coutinho combines well with Alaba and jinks in to the box from the left. He does well to create himself some space but the shot is straight at Jose Sa.
10' - Gnabry is dumped to the ground over on the left touchline by Elabdellaoui but the home side's skipper escapes a booking.
7' - Coutinho whips a ball from left to right to Müller who recovers from a poor first touch to hook a hopeful one in to the area. It falls to the Brazilian but his effort on the bounce deflects behind. Martinez gets up highest from the corner but can't control the header under pressure.
5' - Bayern controlling possession now, though mostly by stroking it across the pitch in their own half.
2' - Kimmich gives away an early free kick in a dangerous position on Bayern's right but it's easily cleared.
1'- The anthems are sung, the players are in position and the visitors get the game underway.
All over in Madrid, where the home side won a tepid game to go top of Group D with seven points. Juventus will join them later if they can beat Lokomotiv Moscow while Leverkusen have no points and just one goal from their three games in the competition this year.
Leverkusen on the brink
A header from substitute Alvaro Morata has given Atletico Madrid the lead against Bayer Levekusen in Spain. That'll make it no points from three games for the German side, who'd be all but out of the competition.
Olympiacos condemn fan violence
The home side have released a press statement in relation to the reported incidents mentioned a couple of entries below this.
"Olympiacos most emphatically decries this afternoon’s invasion of hooligans into the Rentis Training Center. These intruders have nothing to do or no relation whatsoever with the Olympiacos family."
Complete with the obligatory headphones, Bayern are in the Karaiskakis Stadium. Yes, I had to copy and paste that.
Goalless in Madrid at the break
Not a classic in the Wanda Metropolitano, scene of last season's final. Leverkusen have probably just about edged it and looked unusually secure at the back but it's been pretty uninspiring from both sides so far.
Müller in starting XI
Bayern have announced their team and there's a rare start for Thomas Müller, his first in the Champions League this season, alongside Coutinho. Javi Martinez also makes the XI, most likely in midfield, with Benjamin Pavard and Lucas Hernandez as the center backs.
Reports of violence ahead of match
News agency AP, among others, are reporting that there were violent clashes between fans earlier today. Greek police say four visiting Bayern fans were injured during an attack by suspected Olympiacos supporters earlier today.
"Police said about 80 men, many in motorcycle helmets or armed with clubs, invaded a training ground in Athens where the Olympiacos and Bayern Under-19 sides were playing and started battering Germans in the stands," reads the report.
The extent of the injuries is unknown and no arrests have been reported.
The view from the opposition
Olympiacos coach Pedro Martins seemed fairly relaxed when discussing the visitors from Bavaria in his press conference.
“In my career, there have been matches to consider finals; I said so at the onset of the season. Such a match has been the one against Victoria Plzen. My eyes were set on the objective of making it to the group stage, our efforts and preparation for that and so on," he said.
"We want to put our strengths to the test. But these are things to see tomorrow. However, I cannot say it’s a final. It will be a great match, but, definitely, will not be as crucial as you mentioned”.
Boateng back in the picture
--One man who might benefit from Süle's injury is Jerome Boateng. The World Cup winner's spell in Bavaria looked over in the summer but he's forced his way back in to contention and is now the only fit, experienced, natural center half in Kovac's squad. There's plenty of talk of Mats Hummels returning to the national team set up but little about his long term defensive partner for club and country. Could that all change with a run of good displays for Boateng?
German interest in early game
-- The other German team playing tonight, Bayer Leverkusen, travel to face Atletico Madrid knowing a loss will leave their hopes of qualification hanging by a thread after defeats in their first two games. Here's how the Werkself line up.
Alaba not complacent
-- Bayern have a perfect record from their four meetings with tonight's opponents but David Alaba isn't taking it lightly.
No shortage of storylines
-- As usual, there's plenty of storylines swirling around Bayern before this one. The long term injury to Niklas Süle leaves Bayern short of center back options and may lead to an increase in playing time for Javi Martinez, one of a number of players rumored to be unhappy. Another of those is Thomas Müller, whose non-selection has caused waves in Germany, with club president Uli Hoeness recently going public to defend Niko Kovac over the absence of the Germany star from the teamsheet.
"It was clear that if (Coutinho) arrives, it will be more difficult for Thomas," he said ahead of this one. Plenty of eyes on that teamsheet.
Can Bayern bounce back?
-- Hello! Welcome to DW's live coverage of Tuesday's Champions League clash between Bayern Munich and Olympiacos. After a shock 2-2 draw against Augsburgin the Bundesliga, the German champions travel to the Greek capital looking to bounce back into form.
Follow us here and on Twitter at DW Sports for all the updates leading into the match and all the live action from kickoff!