Gregory Pujol scored the only goal as Valenciennes pulled seven points clear of the Ligue 1 relegation zone with a narrow victory at Reims.
Hubert Fournier's men went close through Nicolas Fauvergue and Diego Rigonato in the first half but the visitors would steadily turn the screw and earn all three points when Pujol beat the impressive Kossi Agassa in the 57th minute.
The result leaves Reims in 14th place and just four points from safety with five games remaining while Valenciennes' first win in nine sees them climb to 12th.
There were 13 minutes on the clock when Diego crossed in from the right for Fauvergue to smash a volley inches wide of the post.
Valenciennes responded well by forcing two fine saves from Agassa.
First, Younousse Sankhare benefited from good work by Maor Melikson to force a block from the Togolese stopper before Kenny Lala saw his right-footed strike saved.
Three minutes before the break Diego shot at Nicolas Penneteau first time after being released by Grzegorz Krychowiak, but the Valenciennes keeper was alert to the danger.
It would be a more one-sided second half with VA getting closer and closer until Pujol made the breakthrough shortly before the hour mark.
An overlapping move saw Gael Danic storm down the right wing to reach the by-line.
The Vannes-born midfielder crossed into the box for Pujol, who skilfully dummied Agassa to clip home with his right boot.
Remi Gomis then took his time with Melikson's cross in the 71st minute but Agassa used the extra breathing space to shape his body for a comfortable stop.
Reims showed few signs of forcing a late equaliser and it might have ended 2-0 to the away side had Opa N'Guette managed to beat Agassa with a low drive deep into stoppage time.