Munster beat Lions in their final regular-season game to qualify for the BKT URC play-offs and guarantee Champions Cup rugby next season.
Starting the game in ninth place, the 24-17 win moved Clayton McMillan's side up to fifth and they will face the Bulls away in the quarter-final.
The result also ended Ulster's URC season as they dropped to ninth, however, Richie Murphy's side can still qualify for the Champions Cup should they beat Montpellier in next weekend's Challenge Cup final.
Connacht, who beat Edinburgh last night, finished in eighth place and will face table-toppers Glasgow in their quarter-final clash, while they won't know their European destination for next season until late on Friday night after Ulster's final.
Earlier, Leinster easily beat Ospreys to secure second place in the table and they will host the Lions in their quarter-final in two weeks' time.
In Limerick, captain Craig Casey inspired the hosts to the much-needed victory, scoring a try and leading from the front, making light of the late withdrawal of Jack Crowley through injury, and yellow cards for Andrew Smith and Sean O'Brien.
An early try from Evan O'Connell (below), barging through from close range, was soon cancelled out when Lions full-back Quan Horn darted over after 15 minutes.
JJ Hanrahan put Munster back in front with a penalty, before Smith and then O’Brien were both shown yellow cards for deliberate knock-ons.
Kelly Mpeku reduced the deficit late in the first half when he ran in, but Casey edged across before the buzzer to give Munster a slender 17-14 lead at the break.
Tom Ahern gave the home side some breathing space when he crashed over under the posts in the 54th minute after a break from Casey, with Hanrahan adding the extras.
There was a stoppage just after the hour following an allegation of spitting by Munster replacement Diarmuid Barron.
However, but the TMO was unable to verify anything obvious from the Lions players during the rucks.
After a lengthy delay, play resumed with the incident likely to be sent for a disciplinary citing commission.
O’Brien raced back to just deny Angelo Davids as he looked to ground a kick down the line into the right corner as Munster’s defensive line dug in to repel a push from the Lions to see out the closing stages.
Additional reporting: PA
