Sam Davies kicked 17 points as Ospreys came back from a poor first-half performance to seal a crucial Guinness Pro12 win over Edinburgh at the Liberty Stadium.
Scarlets were grateful to a late penalty from replacement fly-half Aled Thomas as they snatched a 22-21 victory in a gripping Guinness Pro12 tussle at Parc y Scarlets.
Edinburgh have been handed a significant boost ahead of their Guinness Pro12 clash with Cardiff Saturday's after Cornell Du Preez and Neil Cochrane both agreed to extend their time in the Scottish capital.
A 79th minute try from Sale centre Johnny Leota secured a bonus-point victory over Pau that all but guarantees the Sharks' place in the Challenge Cup quarter-finals.
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.