Messi scored the first goal for Barcelona
Zlatan Ibrahimovic returned to haunt former side Barcelona as he scored one and set up the other for Paris St-Germain in their Champions League quarter-final first leg.
The Swede stabbed home from an apparently offside position to cancel out Lionel Messi's well-made opener.
Xavi's 89th penalty after Salavatore Sirigu fouled Alexis Sanchez seemed to have secured the win for the Catalans.
But Ibrahimovic's 94th-minute knock-down was swept home by Blaise Matuidi.
Meanwhile, in Germany, Bayern Munich produced an authoritative home performance to leave Juventus facing an uphill task to reach the Champions League semi-finals.
The German league leaders made the perfect start when David Alaba's deflected 35-yard shot spun past Gianluigi Buffon after 25 seconds.
Bayern totally dominated the Italian champions and created several superb chances in the quarter-final first-leg.
But they could not make their dominance count until Thomas Mueller's tap-in.