Treviso were swept 47-10 by Brendon Leonard's Ospreys. Matters were not helped by a red card to Dean Budd.
In the French Top 14, two former Crusaders first fives marked each other at Pau, though the home side went down 25-9 to visitors Toulon. Colin Slade kicked a goal for Pau, while Tom Taylor was opposite him for Toulon. Conrad Smith and Chris King also started for Pau.
A try to David Smith for Castres trumped a score for Tino Nemani for Grenoble as Castres won 33-28 away from home, while Oyonnax and Agen will be battling to avoid automatic relegation after the former fell 31-13 to Brive. Roimata Hansell-Pune, Leon Power and Viliami Ma'afu all started for Oyonnax. George Tilsley's Agen went down 38-10 to a Kiwi-less Clermont.
A try to hooker Hikairo Forbes helped La Rochelle to a 22-15 win over Bordeaux-Begles, for whom Peter Saili was yellow-carded.
Anthony Tuitavake's Montpellier rose to second on the standings with a 26-20 defeat of the struggling defending champs Stade Francais, who started Paul Williams at centre and Zak Taulafo at loosehead prop.
Toulouse, featuring Corey Flynn, Census Johnston, Joe Tekori, Luke McAlister and Paul Perez, edged Racing-Metro 14-3. There was no Dan Carter for the latter, perhaps being rested ahead of a big European clash this weekend.
In the Aviva Premiership, Saracens beat Harlequins 22-12 in front of over 80,000 at Wembley, Ben Botica kicking four goals for Quins. Sale, with captain Sam Tuitupou, Bryn Evans and TJ Ioane all starting, defeated Bath 29-17.
Mike Delany kicked two goals as Newcastle beat London Irish 13-6, with Tom Coventry's Exiles now seven points adrift, propping up the log, of the Falcons with just two to play.
Will Lloyd and Sean Maitland started for the Exiles, while Nili Latu and Tane Takalua formed the 8-9 spine.
A try to Frank Halai for Wasps was overshadowed by an extraordinary six tries to Englishman Christian Wade as they stung Worcester to the tune of 54-35. Charlie Piutau (Wasps) and Bryce Heem (Worcester) both wore the No 13 jersey.
Leicester cemented fourth spot with a 30-24 defeat to Northampton, despite tries to George Pisi and Teimana Harrison.
John Afoa and Jeremy Thrush helped Gloucester to a 16-9 win over Thomas Waldrom's Exeter.
This weekend sees the semifinals of the Champions Cup and Challenge Cup.