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 Hurricanes proved far too strong for the Sunwolves in Super Rugby on Saturday, while the Sharks beat the Reds.
Ryan Baird and Dave Kearney both scored hat-tricks as Conference A leaders Leinster routed Glasgow Warriors on Friday.
Billy Twelvetrees contributed 12 points for Gloucester, but Sale Sharks held on for another Premiership victory.
After three consecutive defeats to start the Super Rugby season, the Waratahs finally got off the mark on Friday.
The IRFU has confirmed the postponement of Ireland versus Italy in the interest of public health.
Absent for the opening three matches of the Six Nations, Anthony Watson is back in the mix for England this week.
Josh Adams will miss the games against England and Scotland as he requires surgery on the ankle he injured against France.
The Ospreys have turned to Toby Booth to take over as head coach when he finishes his assignment with Harlequins.