A much-changed Ospreys side battled hard in Belfast but came away pointless, losing 47-17 to a strong Ulster side.
The Ospreys were disrupted by the late withdrawals of Dan Lydiate and Stephen Myler from the starting side.
It took the Ulster men just over a minute to score the opening try of the match. Jack Walsh sliced his clearance kick from the kick off into touch, the Ulster pack then worked their way towards the line. The awareness of Ian Madigan put centre Luke Marshall in to score. John Cooney converted.
Ospreys prop Gareth Thomas unfortunately had to leave the field after the try after suffering a head injury on his 100th appearance for the club.
The hosts scored their second try of the match in the seventh minute, after winning a turnover penalty in the Ospreys 22, they kicked to the corner. Their driving maul powered towards the line; hooker John Andrew was rewarded with the score. Cooney added the extras.
The visitors responded well; Morgan Morris made an excellent break deep into Ulster territory before being brought down. The hosts were penalised at the breakdown as Ospreys kicked to the corner. Flanker Jac Morgan powered his way over the try line from short range to close the gap. Walsh converted.
Duane Vermeulen showed his quality on his return from Springbok duty, bursting through several Ospreys defenders before passing to Craig Gilroy who then passed inside to Nick Timoney, who was held up superbly over the try line by Walsh and Morgan.
Moments later Ulster did score their third of the evening, once again through the forwards. Their pack kept the ball tight before lock Sam Carter found his way over the line. Cooney again added the conversion.
Walsh kicked a three-pointer for the visitors after Nicky Smith won a scrum penalty on the Ulster 10 metre line.
The hosts secured their bonus point shortly after the half hour mark, Marshall ran a brilliant angle to receive the ball and run in under the posts for his second. Cooney added the extras.
Half-time: Ulster 28 – 10 Ospreys
The Ulster men continued their dominance in the opening stages of the second half, Stuart McCloskey scored after being set up by Mike Lowry out wide. Cooney missed the conversion.
Ospreys worked tirelessly in the midfield in the second period without gaining much ground. On the occasion they were in the hosts 22 they were repelled by the robust Ulster defence.
The experienced home pack did not let the Ospreys rest in defence. Sam Carter scored his second of the evening after a spell of powerful bursts around the breakdown. Cooney added the extras.
The hosts continued with their seventh try, once again from short range, this time through Marcus Rea. Cooney added the conversion again.
Ospreys scored the last try of the game, which was fully deserved after battling hard for the full 80 minutes. Morgan Morris powered his way over the try line to ensure the Ospreys troubled the scoreboard in the second half. Walsh converted.
Full-time: Ulster 47 – 17 Ospreys