Julian Draxler was among the goalscorers as his Paris Saint Germain side hammered Barcelona 4-0. Angel di Maria and Edinson Cavani also scored in a match that will send shockwaves through the competition.
The defeat is Barcelona's biggest since losing 7-0 on aggregate to Bayern Munich in the semi-finals in 2013 and they now appear likely to exit the Champions League before the quarter final stage for the first time in a decade.
Di Maria got the hosts off to a flyer, firing in an 18th minute free kick after Draxler had been fouled just outside the box. The former Wolfsburg winger, making his European debut for PSG, was in fine form and added a goal of his own shortly before the break.
Draxler exchanged passes with Marco Verratti before slotting past Germany teammate Marc-Andre ter Stegen in the 40th minute. The visitors looked shellshocked but there was more to come.
Barca showed a few signs of recovery early in the second period but di Maria again found the net to quell any thoughts of a comeback. The former Real Madrid curled a sublime left-footed strike in to the top corner to finish a move that had started with German keeper Kevin Trapp.
The Argentinian was removed shortly after to a standing ovation but the French side weren't prepared to rest and Edinson Cavani completed the rout in the 71st minute.
Samuel Umtiti almost gave the Spanish champions a glimmer of hope for the return leg late in the match but his effort hit the post. The sides will meet again at Camp Nou on Wednesday March 8.