La Rochelle remain eight points clear at the Top 14 summit after nearest rivals Clermont Auvergne lost for the second week in succession, going down 28-19 at home to fellow high-fliers Montpellier.
Clermont were beaten by Castres last Saturday and suffered another setback as Montpellier bounced back impressively from their loss at Lyon to regain third spot, thanks largely to a fine display from full-back Benjamin Fall.
The visitors initially surged clear with two tries in the space of three first-half minutes at Stade Marcel-Michelin.
Joe Tomane dotted down a loose ball after Fall and opposite number Nick Abendanon had contested a chip to the in-goal area from Francois Steyn. Fall then produced a wonderful offload prior to Yvan Reilhac putting Timoci Nagusa over on the right wing.
Clermont responded with two Morgan Parra penalties, but Montpellier crossed again at the end of the opening period through Bismarck du Plessis, Steyn adding his first conversion to secure an 11-point lead.
The hosts rallied in the second period, Parra splitting the posts again before Damian Penaud's fine break led to Abendanon putting fellow Englishman David Strettle through a gap to cross.
However, following a penalty from Steyn, Fall collected a superb looping pass from scrum-half Nic White to score in the left corner.
And although Montpellier prop Antoine Guillamon was yellow-carded with 12 minutes remaining, after the left boot of Parra had reduced his side's arrears to six points, Clermont could not find the try they needed and a Steyn drop-goal made the game safe for Jake White's men.
Earlier on Sunday, in-form Pau beat Castres 18-12 to replace their opponents in the top four and extend their unbeaten run to eight league matches. Six penalties from Tom Taylor proved enough for Pau to win a try-less affair at Stade du Hameau.