A David Smith try was insufficient to prevent his Castres losing 17-16 to Lyon, who fielded no less than six New Zealanders - Rudi Wulf, Mike Harris, Josh Bekhuis, Ti'i Paulo, Hosea Gear and Toby Arnold.
Montpellier smashed Grenoble 54-14, for whom centre Tino Nemani scored a try and No 8 Steven Setephano copped a yellow card.
La Rochelle, with Uini Atonio, Victor Vito and Jason Eaton in the ranks, are sitting pretty atop the table after their 16-5 victory over Bordeaux-Begles. Hugh Chalmers was yellow carded for the latter, while Jayden Spence scored a try.
In the Aviva Premiership, Sean Maitland's Saracens again flexed their muscles, dispatching Harlequins 40-19. Lions five-eighths lock-in Owen Farrell slotted eight from eight for 20 points. Nick Evans kicked four goals for Quins, for whom Mat Luamanu was at No 8.
Farrell's England teammate George Ford was, according to Bath director of rugby Todd Blackadder, outstanding, as was Wales No 8 Toby Faletau, another Lions contender, in Bath's 27-21 win over Leicester, which keeps the west country club in the semifinals hunt. Kahn Fotuali'i was at halfback for Bath, while Telusa Veainu and Brendon O'Connor scored tries for the Tigers.
Thomas Waldrom scored a brace in Exeter's 38-24 defeat of relegation-bound Bristol, despite a Jason Woodward try for the latter. Also featuring for the vanquished were Jack Lam, Mark Sorenson and Alby Mathewson.
Mike Delany kicked a conversion, which turned out to be crucial, in Newcastle's 16-14 win over Gloucester, for whom Tom Marshall scored a try. Willi Heinz, John Afoa and Motu Matu'u also turned out for the cherry and whites.
Sale, who fielded Bryn Evans, Halani Aulika and Denny Solomona, defeated Chris Vui's Worcester 36-26.
Jimmy Gopperth's five goals were decisive as Wasps edged Northampton 32-30. Ahsee Tuala and Teimana Harrison scored tries for Saints.
In the Guinness PRO12, Lions captain contender Sam Warburton scored a try but limped off in Cardiff Blues' 24-all draw at Ulster. Warburton was replaced by former Ulster favourite Nick Williams. Rey Lee-Lo's brace was vital, as were the four goals kicked by Gareth Anscombe. Jarrad Hoeata and Willis Halaholo were also in the Blues' starting line-up.
Ulster have a playoffs battle with Wayne Pivac's Scarlets, who are in a purple patch, having put 51-5 on Dean Budd's Treviso. Johnny McNicholl and Hadleigh Parkes were again to the fore. Hooker Ken Owens, very much in the Lions' frame, scored a try in his 200th outing for the region.
Three goals by fullback Isa Nacewa helped Leinster to a tight 20-18 win over Kieron Fonotia's Ospreys. The result may have been different if Wales No 10 Dan Biggar, also in his 200th game for the region, had not pushed a late penalty goal wide.
Zebre moved off the bottom of the table with a 29-14 win over Nick Crosswell's Dragons.
A late try to Lions certainty, fullback Stuart Hogg, was not enough for Glasgow, who were defeated 10-7 at Munster. Tyler Bleyendaal kicked a goal for the home side, who also fielded Francis Saili and Rhys Marshall.
Connacht beat Edinburgh 22-19 with a squad that included Bundee Aki, Tom McCartney, Jake Heenan, Dominic Robertson-McCoy, Naulia Dawai and Josh Rowland. Viliami Fihaki and Phil Burleigh played for Edinburgh.
