Jamie Vardy's late strike for Leicester gives the English champions a vital away goal at Sevilla. In Portugal, 10-man Porto's hopes were crushed by a quickfire Juventus double.
Sevilla 2-1 Leicester
(Sarabia 25' Correa 62' - Vardy 73')
Sevilla will take a slender one goal advantage to Leicester after the Premier League champions clawed their way back into the tie courtesy of Jamie Vardy's second half strike.
Claudio Ranieri's Leicester have endured a torrid domestic season and are in serious danger of becoming the first top-flight English team since 1938 to be relegated straight after winning the title. But they've saved their best performances this season for the Champions League, and they demonstrated their fighting qualities to remain well in the contest.
Sevilla started well and could have gone ahead on 14 minutes when they were awarded a penalty after a foul by captain Wes Morgan, but Kasper Schmeichel saved Joaquin Correa's timid penalty, which was straight at him.
The hosts remained in control though and took the lead soon after through the impressive Pablo Sarabia, whose towering header flew into the far corner.
Correa atoned for his penalty miss with Sevilla's second, firing into the roof of the net after good work by Stevan Jovetic.
But Vardy's predatory finish from Danny Drinkwater's perfect low cross from the left put a different complexion on the second leg in three weeks' time, with Leicester still well in the tie.
Porto 0-2 Juventus
(Pjaca 72', Alves 74')
Juventus put themselves in a fantastic position to qualify for the next round of the Champions League on Wednesday night with a 2-0 win away to Porto.
The opening leg of the last 16 tie looked well-matched over the course of the opening 20 minutes, before full back Alex Telles was sent off after two yellow cards for two clumsy challenges.
Although Juventus then dominated possession and the goal-scoring opportunities, it wasn't until late on in the second half that the breakthrough finally came, following some smart substitutions from Massimiliano Allegri.
Some added impetus from Marko Pjaca was almost immediate, when he scored a fortunate one-two just five minutes after entering the field. Two minutes later Dani Alves then knocked in a cross after stepping on to the pitch 60 seconds earlier.
German international Sami Khedira then came close to making it three moments before full time, but his outstretched leg could only flick the ball wide of Iker Casillas' far post.
Porto now face the daunting task of travelling to Turin with the hope of at least matching Juventus' two-goal cushion.