Ospreys centre Keiran Williams scored two tries to help earn his side a 31-9 victory and condemn Scarlets to another derby defeat in Swansea.
Second row Kiran McDonald has become the latest ex-Wasps player to find work after he was made redundant by the club on October 17.
Wasps have signed Scottish lock Kiran McDonald from Glasgow Warriors for next season.
After the euphoria of Thursday's announcement, many of the Lions stars selected to go on this summer's 10-match tour of Australia have domestic matters to attend to this weekend.
New Zealand and Australia have claimed big wins in round two of The Rugby Championship U20s in South Africa, leaving the trans-Tasman rivals as the only undefeated sides after their draw in round one.
The U20s Rugby Championship is both an end in itself but also serves as preparation for World Rugby’s U20 Championship, to be played in June and July.
Cardiff took a huge step towards securing an end-of-season play-off spot with a 36-19 United Rugby Championship victory over Ospreys at the Principality Stadium.
Reeling from more financial strain, and still seeking a new head coach, Wales' summer tour of Japan may offer shafts of light.
The Queensland Reds will welcome back a smattering of Test talent for their top-of-the-table clash with the Chiefs, but won't rush Liam Wright back from his latest shoulder issue.
England lock Ollie Chessum will return to Leicester Tigers' starting XV on Sunday as his side host Saracens in the Gallagher Premiership.