UPDATE 3-Soccer-Leaders Marseille held as champions Lyon lose

* Marseille extend lead to three points

* Ligue 1 top scorer Gignac scores twice

* Lyon beaten 2-0 at Valenciennes

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PARIS, May 2 (Reuters) - Two deflected efforts by Mamadou Niang helped Olympique Marseille draw 2-2 with Toulouse to extend their Ligue 1 lead to three points on Saturday.

The league's top scorer Andre-Pierre Gignac took his tally this season to 21 goals by twice putting visitors Toulouse ahead after the interval.

Marseille have 68 points with four games left, three ahead of second-placed Girondins Bordeaux who host struggling Sochaux on Sunday.

Olympique Lyon's hopes of an eighth successive crown all but vanished when a double strike by Johan Audel led Valenciennes to a 2-0 home win over the champions.