Leinster maintained their unbeaten league record with an 11th straight success in a hard-fought 22-19 win over Ospreys in Swansea.
Ospreys produced a superb fightback to claim a home tie in the last 16 of the Investec Challenge Cup with a dramatic 31-28 win at Pau on Saturday.
Dragons stunned Ospreys 23-21 in the United Rugby Championship thanks to a dramatic converted try by replacement prop Luke Yendle.
The Welsh national team maybe going through a chastening period but there is a rich seam of talent coming through
Jack Crowley kicked 13 points as Munster overcame eighth-place finishers Ospreys 23-7 at Thomond Park to earn a BKT United Rugby Championship home semi-final.
Cardiff were in contention throughout but two tries from international prop Nicky Smith and others from Justin Tipuric and Luke Morgan proved just enough.
Jordan Larmour scored his first senior hat-trick for Leinster as the Irish province produced a second-half masterclass to hammer Ospreys 61-14 at the RDS.
For the Ospreys, the big goal this season has been to earn respect and they will certainly have done just that with their stunning 27-21 bonus point victory over the DHL Stormers in Cape Town.
Ospreys stunned the Stormers in Cape Town to underline their United Rugby Championship play-off credentials by recording a 27-21 victory.