MARSEILLE, France-- A stoppage-time goal from Andre Ayew gave Olympique Marseille a 1-0 win over Inter Milan in the first leg of their Champions League last-16 tie at the Stade Velodrome on Wednesday.

Ayew broke the deadlock with a glancing header in the third minute of time added on from a Mathieu Valbuena corner leaving the Inter players shaking their heads in disbelief as the French side stretched their unbeaten run in all competitions to 16 games.

Inter's best chance of the match came in the 11th minute when Steve Mandanda tipped a Diego Forlan half-volley over the bar.

The return leg will be played at the San Siro on March 13.

The hosts enjoyed plenty of possession but were made to wait until the half hour to threaten Julio Cesar when a free kick landed in front of goal only for Brandao and Souleymane Diawara to get muddled up and put the ball out of play while the Inter defence went AWOL.

The unmarked Mauro Zarate had a chance for the 2010 European champions eight minutes before the break but his low shot was too weak to bother Mandanda.

Inter looked dangerous on the break but the Marseille defence held a high line and increased the pressure in the second half but still struggled to create clear chances.

Joel Obi replaced Zarate shortly after the hour as Inter coach Claudio Ranieri looked to add fresh blood to his front line.

His Marseille counterpart Didier Deschamps replaced Brandao with Jordan Ayew in the 73rd minute but the Ghana forward produced an equally unimpressive performance.

Just when it looked as though Inter were going to keep a rare clean sheet, Andre Ayew popped up to head home a corner with the last move of the game.

Inter, who have lost six of their last seven games in all competitions, have failed to keep a clean sheet since they beat Serie A rivals AC Milan 1-0 on Jan. 15.