Barcelona took back the lead in the 87th minute after Alexi Sanchez earned a penalty and Xavi Hernandez scored to give the visitors a 2-1 lead in the final minutes of the match in Paris.
PSG goalkeeper Salvatore Sirigu made an ill-advised challenge with time running out, taking out Alexis Sanchez's leg and giving Barcelona a penalty. Sirigu appeared to have time to pull away from the challenge but he didn't and Sanchez took advantage. It wasn't a dive from the striker so there won't be much controversy but it will still be a tough pill to swallow for PSG.
Barca captain Xavi Hernandez stepped up and beat Sirigu to the right as the keeper went left and the visitors had the lead back and two away goals to take back home with them.
It's a crushing blow to PSG who'd worked so hard to fight back into the match and will now face a difficult challenge in the second leg.