CJ van der Linde’s Leinster beat Castres 33-3 but they failed to claim a crucial bonus point.
Two late tries inflated the the scoreline, but the Irish team will be livid they didn’t claim the fourth. For Castres, Van der Linde’s former Cheetahs team-mate Darron Nell limped off with what looked a serious leg injury.
Brian O’Driscoll, Bernard Jackman and Simon Keogh scored for the hosts.
Meanwhile Toulouse did claim five points as Freddie Michalak enjoyed the chance to start ahead of injured David Skrela as he kicked three conversions in their 26-7 win over the Newport Gwent Dragons. All the tries were scored by the backs as Yannick Jauzion, Florian Fritz, Clement Poitrenaud and Maxime Medard crossed the line.
Gloucester eased past Calvisano 40-17 with six tries from Ryan Lamb, Luke Narraway, Marco Bortolami, Jack Forster, a penalty try, and Mike Tindall capped off the performance when he crossed the line.
Harlequins caused an upset when they downed Stade Francais in Paris. Jordan Turner-Hall and Tom Williams scored first half tries as they went ahead 12-0. They then fought off a spirited Stade comeback and will look forward to hosting the same opponents at The Stoop next weekend.