The goal came after Charles N'Zogbia gave away possession close to his owngoal - but his team almost equalised immediately through Geremi's header from James Milner's cross.
In the 76th minute, with PSG having to fight hard to hold a lead given to them by an early owngoal from Marseille defender Nicolas N'Koulou, coach Carlo Ancelotti finally threw him into the fray to replace Argentina's Javier Pastore.