Toulon missed an opportunity to go third in the Top 14 when Henry Vanderglas' late converted try salvaged a dramatic 23-23 draw for lowly Grenoble, while Alexis Palisson scored a hat-trick in Toulouse's high-scoring win over Lyon.
Three-time European champions Toulon led 17-7 at half-time courtesy of tries from Romain Taofifenua and Laurent Delboulbes, as well as seven points from the boot of Pierre Bernard.
Maritino Nemani gave Grenoble hope with a try just before the break while Fabien Alexandre was in the sin bin and they trailed by just seven points after Jonathan Wisniewski slotted over two penalties, with Bernard adding a pair himself either side of a yellow card for Liam Gill.
Second-bottom Grenoble were up against it when Laurent Bouchet was yellow carded just after Gill returned, but Vanderglas went over right at the end and Wisniewski added the extras to deny Toulon.
Toulouse ended their four-match losing run with a 42-26 defeat of Lyon thanks to a barnstorming first-half display.
Wing Palisson scored two of four tries in the opening 40 for the home side and another following the interval, with Jean-Marc Doussain helping himself to 17 points from the tee.