Stuart McCloskey marked his 100th Ulster appearance by scoring the only try of the game in an 8-0 defeat of the Ospreys, while Munster hammered the Southern Kings in the Pro14 on Friday.
Centre McCloskey finished seven minutes into the second half of his landmark match in Bridgend as Ulster moved up to third in Conference B.
John Cooney, released from Ireland's Six Nations squad to play for the European Rugby Champions Cup quarter-finalists along with Jordi Murphy, was on target with a late penalty to deny the Ospreys a losing bonus point.
Ulster's Ireland lock Iain Henderson played the full match on his return from a finger injury, staking his claim to play a part against Italy in Rome a week on Sunday.
Munster stretched their winning streak to six matches in all competitions with a 43-0 thumping of the Southern Kings at Musgrave Park.
Andrew Conway and Billy Holland were among seven try-scorers for Johann van Graan's side, who stretched their lead at the top of Conference A to seven points in ruthless fashion.
Duhan van der Merwe claimed a double in a 34-17 success for Edinburgh over the Dragons, who led 17-14 at the break following a brace of Tyler Morgan tries.