Already missing 23 players through injury or international duty, there was a late setback for the Ospreys when Ian Gough was forced to withdraw with a calf problem, Lloyd Peers stepping up in his place off the bench. This in turn led to a reshuffle among the replacements, travelling reserve Tom Grabham coming into the matchday 23, a back for a second row.

Ulster took the lead inside four minutes, Ruan Pienaar slotting over a penalty after Sam Lewis was pinged at the breakdown.

They led for just five minutes or so, Matthew Morgan's penalty bending in between the sticks after seeming set to go horrendously wide, levelling things up after Ulster's Lewis Stevenson came into the ruck from the side.

The Ospreys should really have taken the lead on 11 minutes after a positive move saw them sweep upfield into the Ulster 22. Awarded a penalty, skipper Kahn Fotuali'i tapped and went, and after Scott Baldwin had been brought to ground Morgan went for a drop goal right in front of the posts only to slice his kick, sending it spinning to the right of the posts.

Ulster struck straight back with Pienaar's second penalty on 14 minutes, a long-range effort after an Ospreys offence at the ruck.

Despite trailing as the first half reached the midway point, it was a positive performance from the Ospreys, the pack in particular looking dominant in the early stages, and they got back on level terms in the 22^nd minute when Morgan popped over his second penalty.

The Ospreys then enjoyed a period of intense pressure, patiently going through 17 phases as they pounded on the Ulster line, Scott Baldwin and Morgan both going close, but the home defence were able to stand firm, Richard Fussell eventually chipping ahead which allowed Andrew Trimble to gather and call the mark.

The possession and territory stats were firmly in the Ospreys favour and the Ravenhill crowd were unusually subdued but they found their voice again as Ulster came back to enjoy their best moment of the game, a linebreak from Paddy Wallace putting his team on the front foot, and after Tom Habberfield was penalised for not releasing the tackled player, Pienaar made it 9-6 at the break.

HALF-TIME: ULSTER 9 OSPREYS 6

Having not got the reward that their first half display had probably deserved, the Ospreys returned to the field fired up, looking to move the ball at every opportunity, but again they were unable to find away through the resolute Ulster defence despite considerable possession in the opening minutes of the second half.

They would have been buoyed by the welcome sight of Alun Wyn Jones entering the action just short of the 50 minute mark, the skipper making his long awaited return from injury after damaging his shoulder on Welsh duty against Argentina at the start of November.

As the second half followed a similar pattern to the first, with the Ospreys dominating, Fotuali'i missed with a drop goal attempt, but Morgan had better luck a minute or so later with his third penalty, for tackler not releasing, leaving the scoreboard level once again at 9-9.

Ulster came back at the Ospreys, Pienaar putting them into the corner from a penalty, from which the visiting defence did a wonderful job of disrupting and halting an ominous looking rolling maul from the lineout. The home team kept up the pressure through multiple phases, but resolute Ospreys defence frustrated the Ulstermen, eventually resulting in a penalty to the men in black for players going off their feet at the ruck.

Having survived that scare the Ospreys were unable to gain any respite as Ulster piled the pressure on, going through 16 phases, before a controversial moment that derailed all their good defensive work when referee Marius Mitrea penalised Morgan Allen for not releasing in the tackle in the shadow of the posts. Allen was shown yellow and Stuart Olding slotted over the penalty to put Ulster ahead once again,

The Ravenhill roar was back as they sensed a crucial 10 minutes with the Ospreys down to 14, but they were stunned into silence a minute later as the visitors struck back with the first try of the night, an incredible length of the field score.

Jonathan Spratt sparked the move with a break from inside his own 22 close to the left touchline. He carried to halfway before offloading to Fotuali'i on his outside, who in turn found prop Ryan Bevington who was able to hare forward almost 40m to score, Morgan's conversion giving the Ospreys a four point lead with 13 minutes left.

The remainder of Allen's time in the sinbin was spent with Ulster pressing the Ospreys line, going through multiple phases as they pounded the line but wave after wave of white shirts were repelled and frustrated, heroic defence eventually resulting in a turnover, allowing the Ospreys to clear.

The Ospreys were back up to 15 with five minutes remaining on the clock, and although they were stretched at times as Ulster looked to run it from everywhere and anywhere, they were able to see out the final stages and secure a memorable win over the league leaders.