Clermont outclassed Grenoble at Stade des Alpes six tries to two to claim a 12-45 victory in the Top 14 on Friday.
As a result les Jaunards move into first place ahead of Toulon and Racing 92.
France winger Noa Nakaitaci, discarded by new head coach Guy Novès, finished with a hat-trick as Clermont ran six tries past their hosts.
Clermont started fast, putting the ball through the hands of their backline before eventually the move was finished off by David Strettle in the corner.
A stunning team try followed two minutes later, started by Paul Jedrasiak and involving Scott Spedding, Fritz Lee, Wesley Fofana and finally Nakaitaci with an inside pass to Jonathan Davies. Parra converted both scores to make it 14-0.
Clermont just couldn't be stopped, a third try coming after just eight minutes into the game as Nakaitaci went over, despite replays suggesting that Camille Gerondeau had obstructed a Grenoble player in the air in the build-up.
Unbelievably Clermont had a fourth try by 18 minutes. Fofana burst through a gap before Davies unleashed Nakaitaci, the winger selling a dummy towards Spedding to race under the posts.
Grenoble finally hit back from a five-metre scrum as number eight Rory Grice powered over.
Clermont lost John Ulugia to a yellow card for a no-arms tackle, followed by Grenoble's Tino Nemani before the end of the half, only after Nakaitaci had grabbed his hat-trick try thanks to more good work from Spedding.
A Morgan Parra penalty prior to the break meant that Clermont took an enormous 38-5 lead into half-time.
The subdued start to the second half was punctuated by a yellow card for Clermont replacement Peceli Yato, as Grice grabbed his second try from short-range.
But it was Clermont who rightly had the final say, replacement scrum-half Enzo Sanga pouncing on loose ball at the Grenoble scrum to make it six tries on the night.
Tries: Grice 2
Yellow Card: Nemani
Tries: Nakaitaci 3, Strettle, Davies, Sanga
Cons: Parra 5, James
Yellow Cards: Yato, Ulugia
Grenoble: 15 Gio Aplon, 14 Tino Nemani, 13 Chris Farrell, 12 Fabien Estebanez, 11 Armand Battle, 10 Jonathan Wisniewski, 9 Charl McLeod, 8 Rory Grice, 7 Fabien Alexandre, 6 Henry Vanderglas, 5 Hendrik Roodt, 4 Ben Hand, 3 Dayna Edwards, 2 Arnaud Heguy, 1 Fabien Barcella
Replacements: 16 Loick Jammes, 17 Sona Taumalolo, 18 Mathias Marie, 19 Steven Setephano, 20 Christophe Loustalot, 21 Nigel Hunt, 22 Fabien Gengenbacher, 23 Walter Desmaison
Clermont: 15 Scott Spedding, 14 David Strettle, 13 Jonathan Davies, 12 Wesley Fofana, 11 Noa Nakaitaci, 10 Camille Lopez, 9 Morgan Parra, 8 Fritz Lee, 7 Alexandre Lapandry, 6 Camille Gerondeau, 5 Sébastien Vahaamahina, 4 Paul Jedrasiak, 3 Dan Kotze, 2 John Ulugia, 1 Raphael Chaume
Replacements: 16 Zak van der Westhuizen, 17 Vincent Debaty, 18 Arthur Iturria, 19 Peceli Yato, 20 Enzo Sanga, 21 Brock James, 22 Isaia Toeava, 23 Clément Ric
Referee: Jérôme Garcès
Assistant Referees: Salem Attalah, Laurent Breil
TMO: Mourad Zitouni