Facundo Isa's late try snatched a 19-15 Top 14 victory for Toulon at Stade Francais and Lyon continued their impressive start to the season with a win over Castres on Sunday.
Toulon were soundly beaten at Montpellier last weekend, but responded by edging out Stade after the boot of Morne Steyn looked to have settled it at Stade Jean-Bouin.
Josua Tuisova scored the only try of the first half and added a second to bring Toulon level at 12-12 midway through the second period following four penalties from Steyn.
A drop-goal from South African fly-half Steyn put Stade back in front 11 minutes from time, but new signing Isa - in his second spell at the club - went over two minutes from time to give Toulon a third win of the season.
Lyon are up to third after a four-try 31-12 home success against Castres.
Toby Arnold, Mickael Ivaldi and Alexis Palisson scored first-half tries to put Lyon in command and Baptiste Couilloud added another after the break in a commanding display from Lyon.