Behind goals from Lionel Messi and Dani Alves, Barcelona secured a 2-0 away victory over Manchester City at the Etihad Stadium.
With the return leg scheduled at the Nou Camp for March 12, City will be facing a near-impossible task, needing a 3-0 victory in order to qualify for the quarterfinals.
The first half was tightly contested, with City having some goal-scoring opportunities despite Barcelona dominating possession.
The match turned in the eighth minute of the second half when Messi was taken down from behind by City defender Martin Demichelis just inside the penalty box (although replays suggested the foul may have occurred just outside the box). Demichelis received a red card and Messi stepped up to put Barcelona ahead.
City kept on pressing despite the man disadvantage, and David Silva came close to an equalizer only to be denied by goalkeeper Victor Valdes.
Despite City’s effort, Barcelona continued to enjoy the majority of possession in the second half and secured the victory in the final minute when Dani Alves added a second goal off a brilliant pass from substitute Neymar.