Ulster notched up their third consecutive PRO12 win to keep them set for a top-four finish as they just about overcame Glasgow Warriors 13-10 at a damp Kingspan Stadium.
Glasgow ended a frustrating European campaign on a positive note and head coach Gregor Townsend was "delighted" with the workmanlike 22-5 victory over Racing 92 at Kilmarnock's Rugby Park.
Glasgow flanker Ryan Wilson has escaped suspension after the charge that he grabbed the testicles of Northampton scrum-half Lee Dickson were dismissed.
Northampton director of rugby Jim Mallinder admitted he was "pretty chuffed" after his son Harry scored the game-winning try a minute from time against Glasgow to keep Saints alive in this season's European Champions Cup.
Glasgow Warriors have opted to move their European Rugby Champions Cup match against Racing 92 on January 23 to Kilmarnock's Rugby Park due to a high risk of their Scotstoun pitch being waterlogged.
Edinburgh capitalised on the late change of venue for the second leg of the 1872 Cup to beat Glasgow Warriors 14-11 and retain their hold on the Scottish title.
Edinburgh sent Glasgow packing empty-handed from the capital for the second season running as the Gunners took a step towards reclaiming the 1872 Cup with a 23-11 first-leg win.
Glasgow Warriors marked their 100th game in the European Cup by doing the double over Guinness PRO12 rivals Scarlets to stay in the hunt for a quarter-final place in the European Champions Cup.
Following a postponement in Paris and a home defeat to Northampton, Glasgow scored six tries to win their first European game of the season, beating Scarlets 43-6.