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.
The Ospreys’ unbeaten record against South African opposition in the United Rugby Championship came to an end with a 61-24 defeat by the Bulls.
Gloucester fly-half Adam Hastings is set to make his return from injury on Friday against the Ospreys in the Challenge Cup quarter-final at Kingsholm.
Wales co-captain Dewi Lake is set to switch from his usual position of hooker to openside flanker for the first time since age-grade rugby to help his injury-hit Ospreys side.
The Ospreys completed the double over west Wales rivals Scarlets as they won their first league game at Parc Y Scarlets since 2015 with a 25-11 triumph.
Benetton produced a late scoring burst to defeat United Rugby Championship opponents the Ospreys 18-13 at Stadio di Monigo.
The Sharks and the Ospreys meet in a historic match at the Twickenham Stoop on Friday night, as it will be the first time a United Rugby Championship match has ever taken place in England.