La Rochelle held off a stirring Toulouse fightback to storm back to the French Top 14 summit with a 27-21 win on Sunday.
Having already earned impressive wins at Toulon and Castres this season, unfancied La Rochelle claimed a third major scalp on their travels.
And a brave stand on their own tryline at the end of the game also denied four-time European champions Toulouse even the losing bonus point.
Tries from Jone Qovu and Pierre Aguillon set La Rochelle on the way to victory while Australian fly-halves Zack Holmes and Brock James kicked the rest of the visitors' points.
Joe Tekori and Julien Marchand crossed for Toulouse but the defeat left them in eighth and four points off the top six play-off places.
Holmes gave La Rochelle an early lead from the tee in a brutal first half and then added three more penalties before being forced off injured to be replaced by compatriot James.
Sebastien Bezy, meanwhile, had kicked two penalties for the hosts, who trailed 12-6 at the break.
Toulouse showed more purpose at the start of the second half and Samoa lock Tekori barged over for the opening try of the match, but Bezy missed the conversion leaving La Rochelle a point ahead.
James kicked his first penalty before La Rochelle stole a Toulouse line-out deep in their own half and broke at pace.
They spread the ball wide to the left, over to the right and then when it came back to the left, Fiji international forward Qovu blasted through wing Arthur Bonneval to score.
La Rochelle's huge pack then got the shove on from a five-metre lineout to push centre Aguillon over the line.
But Toulouse came straight back up the pitch to get their own pushover try through hooker Marchand.
The hosts dominated the final exchanges but couldn't force a game-winning try.
Stade Francais maintained their fine home form to boost their survival hopes with a bonus point 32-9 win over Bordeaux-Begles.
The bonus point was in the bag by half-time as the back three of Fiji flyer Waisea Nayacalevu, full-back Djibril Camara, with a mazy individual effort, and wing Jeremy Sinzelle all crossed the whitewash.
Jules Plisson kicked five penalties and a conversion while New Zealander Simon Hickey, with two penalties, and Ireland's Ian Madigan with one scored the visitors' points.
Hard-hitting Carl Fearns guided Lyon to an upset 16-3 victory over Montpellier in a bruising clash.
The English No.8, signed to play for Gloucester next season, inspired a pack that outmuscled that of a Springbok-laced Montpellier boasting the likes of the Du Plessis brothers, Bismarck and Jannie, in the frontrow, and Jacques du Plessis and Paul Willemse at lock.
La Rochelle lead by four points as Clermont dropped to second due to a 26-16 loss at Castres on Saturday.
Last year's Top 14 finalists Racing 92 and Toulon also both lost, 19-10 to Grenoble and 15-5 to Brive respectively, while rock-bottom Bayonne held Pau to a 25-25 draw.