N'Guessan deservedly pulled them within touching distance in the 73rd minute with a powerful header, but any hope of an unlikely point was short-lived as Olofinjana diverted Jason Koumas' goal-bound effort home.
And after Rodallega missed two early opportunities, the first a header, the second a low drive easily held by Lukasz Fabianski, it was N'Zogbia who created the opening goal.