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.
Southern Kings and Benetton Treviso both fell short on Welsh soil as Scarlets and Cardiff Blues earned Pro14 wins.
Lyon and Toulouse were both winners in Sunday's Top 14 action, with Patricio Fernandez impressing for the former.
Eddie Jones' team selection for England's crunch Six Nations clash with Ireland raised eyebrows, but his side responded in style on Sunday.
Exeter plundered eight tries in a crushing victory over Northampton as they took another step closer to finishing top of the Premiership.
Bordeaux Begles gave another demonstration of their Top 14 title credentials with a bonus-point win over Clermont Auvergne.
After losing to Ospreys, Ulster bounced back by defeating Cheetahs, while Glasgow Warriors beat Dragons to move into third in Conference A.
There was a shortage of free-flowing rugby on a damp day in Cape Town, but Super Rugby leaders the Stormers got the job done.