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The hosts took the lead in the 33rd minute when Mathieu Dossevi converted a right-footed shot from close range.
Valenciennes doubled their advantage just two minutes later when Dossevi was found by Majeed Waris, allowing the striker to grab his second of the night.
Waris turned from provider to scorer after the break as he collected a pass from Tongo Hamed Doumbia to slot home with his left and seemingly put the game out of sight.
However, Bastia rallied late on and grabbed a promising goal back through Romaric in the 71st minute, before Ilan Araujo tucked home on the counter to bring the visitors within touching distance with eight minutes to play.
However, the comeback wasn't to be as Milos Krasic wasted a great chance in the final minutes by dragging his shot from close range wide of the keeper's post.