Leaders Racing 92 suffered their heaviest defeat of the season on Saturday as they were humbled 60-7 by Montpellier in Top 14.
With a number of their French stars on international duty in the Six Nations and Dan Carter injured, Racing were immediately under pressure as Bismarck du Plessis went over for the game's first try after six minutes.
Another three Montpellier scores before the break plus three kicks from Demetri Catrakilis gave the hosts a 27-0 lead, but they were far from finished.
Timoci Nagusa scored one of five second-half Montpellier tries, his second of the match, as Racing conceded a further 33 points, with only a converted Etienne Dussartre try a mere consolation for the visitors.
"We were beaten everywhere," said Racing fly-half Remi Tales. "We knew that Montpellier were very strong, we knew in advance that we could not let them play, but I think we watched them play for 80 minutes. We must congratulate them."
Defeat hands the initiative to Clermont Auvergne – who play Toulouse on Sunday – while Montpellier climb a place into fourth.
At the bottom, Stade Francais kept their survival hopes alive with a 33-20 win over La Rochelle, Djibril Camara scoring two of their five tries as they bounced back from three successive defeats.
Stade Francais were not the only strugglers to claim a win, though, as Pau and Oyonnax both picked up victories.
Six penalties from Colin Slade inspired Pau to a 21-16 win over Castres, while Oyonnax lifted themselves off the bottom with a 30-28 win over Agen – who replace them at the foot of the table.