Conference A leaders Munster claimed the win but a performance full of heart saw the Ospreys secure a losing bonus point at the Liberty Stadium
Munster were ahead inside five minutes, the first try of the night coming from a lineout on the left on the Ospreys 22. The visitors went through a series of close range drives to suck in defenders before moving it back wide where Sweetnam sidestepped the last man to score, JJ Hanrahan with the extras.
The scores were level in the 20th minute, Keelan Giles lively up the left wing before dinking it behind the defence. Matthew Aubrey contested the ball on the Munster line with Rhys Marshall, before it bounced loose for Dirksen to collect and score probably the easiest of his 36 Ospreys tries.
Referee Stuart Berry referred it upstairs to check an offside and knock on but the try was good and Luke Price added the two.
Dirksen then had to be alert to snuff out the danger on his own line after Mike Haley had kicked through, Aubrey tidying up and clearing to touch from the dead ball area.
Munster may have been enjoying more possession but good defence from the Ospreys was limiting their chances and, as the visitors frustration started to grow, so did the penalty count.
An offside call against Haley just after the half hour gave Price a clear shot at goal and he made no mistake from 40m out to put the Ospreys in front.
The visitors then used their pack to bludgeon their way forward from a throw on their right but the Ospreys were able to hold them up over the line.
Munster kept up the pressure at the resulting scrum, centre Dan Goggin going for the line before the forwards opted to keep it tight to drive for the line. There was a suspicion that a Munster player may have got the ball down against the post for a try and it was referred upstairs, the eventual call penalty try and a yellow card to Sam Cross for preventing a try scoring opportunity on the line.
HALF-TIME: OSPREYS 10-14 MUNSTER
Cross returned to the action almost six minutes into the second half with no further damage on the scoreboard, the Ospreys trailing by four.
A huge shove at the scrum was rewarded with an Ospreys penalty, to huge cheers from the home crowd, and after a dust-up between the packs, Price put the Ospreys up into the opposition 22, only to see lineout misfire and possession handed back to the visitors.
As the contest headed towards the three-quarter mark it had become a real arm-wrestle, both sides struggling to impose themselves on the opposition, while the home team were getting increasingly frustrated as what seemed a lack of clarity at the breakdown.
An excellent kick chase to Price’s up and under, followed by great work on the ground secured the Ospreys a straightforward shot at goal from 25m out and Price reduced the deficit to a point with 16 minutes to play.
Back came the Irish side and after an incredible spell of pressure, Munster going through more than 30 phases inside the Ospreys 22 and with defenders being sucked in, they eventually ended up with men over out wide and it was a simple walk over for Haley to score.
Hanrahan really should have moved Munster more than a converted try clear inside the final 10 but he pushed his kick wide, leaving Munster’s advantage at six points.
There was a late push from the Ospreys to pinch the win, a penalty at the scrum allowing Price to put them back into the corner. However, Munster won the ball at the lineout and were able to play out the final minutes safely.