The France international headed home in the 82nd minute to add to the opener scored from the penalty spot by Mamadou Niang six minutes earlier.

Nancy were reduced to 10 men as a result of the penalty incident, David Sauget sent off for deliberate handball, but they managed a leveller through Sebastien Puygrenier with 10 minutes left.

With Lens and Bordeaux losing elsewhere on Wednesday, OM are now two points clear in the second Champions League berth.

There were few clear-cut chances in a largely uninspiring first half.

Marc-Antoine Fortune shot over from distance in the 16th minute for Nancy, while Kim had the visitors' two other opportunities towards the end of the half.

Marseille's only real attempt on Nancy's goal came on the half-hour mark following a Samir Nasri corner.

Toufilou Maoulida's original header was blocked on the line and Renato Civelli's follow-up failed to trouble goalkeeper Sebastien Hamel.

Nancy frustrated OM by putting plenty of men behind the ball in the second period, and the hosts' passing was horribly off target as the crowd grew restless.

They needed a stroke of fortune - and they got it in the 76th minute.

A Cisse shot deflected up off Hamel onto the arm of Sauget, who was positioned on the line.

The defender was harshly dismissed for deliberate handball and Niang punished them further by dispatching the penalty into the corner.

OM's lead lasted four minutes, Puygrenier heading a Kim corner home at the near post to provide the Lorraine club with an equaliser.

Cisse had the last laugh though, the on-loan Liverpool striker nodding Mathieu Valbuena's left-wing cross in from eight yards out to hand OM maximum points.