Damien Chouly's try with four minutes remaining allowed Top 14 leaders Clermont Auvergne to a seal a hard-fought 19-18 success at Toulon on Sunday.
Clermont had seen their lead at the top cut to two points by victories for both Montpellier and Racing 92 earlier in the weekend, and they trailed for almost all of this contest.
Toulon - who lost Drew Mitchell and Guilhem Guirado to injury in the first half - were 9-0 in front inside the first quarter of the match through the boot of Jonathan Pelissie, although the lead was down to three by half-time thanks to two kicks from Morgan Parra.
The theme continued in the second period, as three more Pelissie penalties and two from Parra meant Toulon led 18-12 with time running out.
But the definitive moment came when Alifereti Raka got free down the right wing and slipped the ball inside to flanker Chouly, who had the simplest of tasks to touch down under the posts.
Parra added the simple extras and Clermont held out, moving six clear at the top, while Toulon were left to settle for a losing bonus point.