Gael Danic's 79th-minute penalty ensured Valenciennes claimed a point at Lorient.
Danic slotted home from the spot late on after Lorient defender Arnaud Le Lan had handled in the area.
The hosts had taken a third-minute lead through Kevin Monnet-Paquet's low strike, their first chance of the game, but Le Lan's error cost them dear and they remain ninth in Ligue 1 - five points and two places better than tonight's opponents.
Lorient were looking for revenge, having suffered a 6-1 defeat against Valenciennes earlier this season.
And they could not have wished for a better start as they took the lead with their first real sight at goal.
Monnet-Paquet played a one-two with strike partner Jeremie Aliadiere before driving low past Valenciennes goalkeeper Nicolas Penneteau from the edge of the area.
The visitors were nearly on level terms soon after, though, with Mathieu Dossevi dribbling past Lorient captain Bruno Manga before curling against the crossbar.
Les Merlus attempted to make full use of their let off and Penneteau had to be at his best to deny Aliadiere's volley and Maxime Barthelme's low strike.
Penneteau's opposite number Fabien Audard kept out Cameroon striker Vincent Aboubakar's volley from just outside the box to protect Lorient's lead.
The Cameroon striker then volleyed inches wide after the interval, while Audard kept out Gregory Pujol's snap shot from 20 yards.
Lorient were also a threat going forward and Barthelme went close with his effort that went narrowly over the bar.
But their inability to grab an all-important second goal came back to haunt them when Danic sent Audard the wrong way from the spot 11 minutes from time after Le Lan had handled in the area.
Christian Gourcuff's men still had an opportunity to retake the lead, but Penneteau made a fantastic save from Manga's close-range header.