Wales international Dan Biggar played his first game for Northampton Saints as English Premiership side completed a 26-13 victory over Ospreys in the pre-season friendly in Bridgend.
Craig Gilroy scored a double as Ulster thumped Ospreys 35-17 in the Pro 14 play-off in Belfast to book a place in the next season of European Champions Cup.
Ospreys kept their hope of European Champions Cup qualification alive as they went on to seal a 39-10 bonus point victory over Connacht in their Pro 14 clash in Swansea on Friday.
A strong second-half upsurge helped Bath Rugby secure a home semi-final in the Anglo-Welsh Cup with a 32-19 bonus-point win over the Ospreys at the Liberty Stadium on Friday.
Clermont Auvergne secured a home quarter-final berth in the European Champions Cup following a 24-7 win over Ospreys at Stade Marcel-Michelin on Saturday.
An injury to Billy Vunipola put the defending champions Saracens in trouble as they went on to draw the European Champions Cup encounter against Ospreys 15-15 at Liberty Stadium.
Saracens have received a major boost ahead of their upcoming European Champions Cup clash against Ospreys with Wales international Liam Williams declared fit.
Replacement Josh Macleod scored the decisive try in the added minutes as Scarlets completed a 12-9 victory over Ospreys in their Pro 14 encounter in Llanelli on Tuesday.
Northampton Saints suffered their ninth defeat in 10 games spread across all the competitions after they were beaten 32-43 by Ospreys in the latest round of European Champions Cup at Franklin's Gardens on Saturday.
Ospreys have confirmed that Wales international Aled Davies will join the Pro 14 club from Scarlets ahead of the next season after signing a two-year contract.