Top 14 strugglers Stade Francais earned a hard-fought 33-30 victory over European hopefuls Toulon in Paris on Sunday.
Morne Steyn and Anthony Belleau were both in fine form with the boot in a frenetic contest which was settled by Kylan Hamdaoui in the closing stages.
Three successful Belleau penalties put Toulon into a 9-3 lead, but Stade Francais struck back through Steyn's pinpoint kicking and Sekou Macalou's try.
Julian Savea's try early in the second half put Toulon back in front, but their lead was short-lived when Macalou crossed for a second time five minutes later.
The match seemed to have slipped away from Stade Francais when Raphael Lakafia went over but, with seven minutes remaining, Hamdaoui found his way through.
Steyn added the extras, with Toulon unable to mount another comeback as lowly Stade Francais claimed a morale-boosting win.
Bordeaux-Begles, meanwhile, made a statement with a 42-15 demolition of defending Challenge Cup champions Clermont Auvergne.
Having lost 25-23 to league leaders Lyon last time out, Bordeaux returned to winning ways in convincing fashion.
With Ben Botica in superb form with the boot, second-placed Bordeaux ran in five tries as Clermont were twice reduced to 14 men.
Thierry Paiva, Seta Tamanivalu, Santiago Cordero, Yann Lesgourgues and Jean-Baptiste Dubie all got themselves on the scoresheet to make light work of last season's runners up Clermont – who had won their previous two outings.