Fly-half Finn Russell will play no part in the Six Nations, but could make his Scotland return later this year.
Ben Botica scored two second-half penalties to help Bordeaux Begles to a 26-24 victory in a tightly contested match against Castres.
There was no debut victory for Bath new boy Rhys Webb as Bristol Bears continued their charged at a packed Rec.
Peter Robb's dismissal did not prevent Connacht from closing the gap to the Scarlets to only two points ahead of their clash on Friday.
Racing 92, Clermont Auvergne, Bayonne, Pau and Brive earned victories in Top 14, with leaders Bordeaux-Begles not in action.
Munster and Dragons earned home Pro14 victories over Scarlets and Cheetahs respectively.
There were wins for Harlequins, Saracens and Leicester on a dramatic day of Premiership action.
The Stormers and the Bulls suffered disappointing home defeats in Super Rugby, with the Blues and the Jaguares emerging triumphant.
The return of Sharks captain Lukhanyo Am was a timely boost as the travelling side saw out a successful Australasian tour by hammering the Reds 33-23...
The Hurricanes proved far too strong for the Sunwolves in Super Rugby on Saturday, while the Sharks beat the Reds.