"I think everyone stepped up to the occasion tonight in terms of commitment," said Gignac after the game.
"That's what was asked of us - to have, at the very least, a serious warrior's mentality. It was a tough match; Valenciennes are playing for their lives and so are we. But now, we're fifth again, and we're only six points behind Lille.
"I hope we can keep it up, because we have two home games coming up, two very important matches. Our fans were great tonight."
Marseille's next fixture sees them welcome Toulouse in Ligue 1 on Sunday.