Ulster eclipsed Ospreys challenge with a 46-26 win to secure a Pro12 play-off spot as Ospreys failed to qualify for the next year's European Champions Cup tournament.
In an entertaining 10-try match at the Liberty Stadium, Ulster's six were scored by Paddy Jackson (16'), Rory Best (27'), Andrew Trimble (40'), Chris Henry (56'), Stuart Olding (69') and Franco van der Merwe (77').
Jackson, the fly-half, also kicked five successful conversions along with two penalties accumulating a total of 21 points thus playing a pivotal role in Ulster's 20-point victory.
Ospreys managed to score four tries with Dan Biggar (12'), Josh Matavesi (36') and Tom Grabham (66', 75') managing to cross the line.
Biggar also scored three penalties for Ospreys, however, the fly-half's efforts proved inadequate as Ulster managed to hold on to their advantage.
Coming in the second-half, Ospreys trailed merely by seven points. However, they conceded an early penalty on the 42nd minute to Ulster which was successfully scored by Paddy Jackson.
From that point Ulster took charge of the proceedings as Henry's try and Jackson's conversion on the 56th and 57th minute respectively extended their lead to 15 points.
Despite a 22-point trail in the concluding five minutes, Ospreys continued to make attempts at scoring tries.
Grabham managed to get over the line on the 75th minute as Biggar successfully made the conversion reducing the deficit to 15 points.
However, van der Merwe's 77th minute try for Ulster sealed the proceedings and crashed Ospreys' European hopes for the next season.
This win for Ulster has now placed them against Connacht at Galway in the Pro12 semi-final.