Scarlets 22-13 Ulster
Ulster's chances of reaching the Champions Cup quarter-finals evaporated as they slumped to defeat against Scarlets in Llanelli.
Neil Doak's side trailed 12-0 at the break but forced their way back into the game thanks to Darren Cave's try just after the restart.
Despite losing Declan Fitzpatrick to the sinbin they closed to within two points with eight minutes to go, thanks to the kicking of Ruan Pienaar.
The South African missed the 75th-minute penalty that would have put Ulster 16-15 ahead however, and James Davies' intercept try two minutes from time decided matters.
Scarlets were forced into a late change when Wales lock Jake Ball pulled out with a virus, with George Earle coming into the second row.
For Ulster, centre Luke Marshall returned after recovering from a knee injury sustained playing for the Ulster Ravens in October.
It was Scarlets who made the early inroads on the scoreboard, opening up a 6-0 lead in the opening quarter through two Rhys Priestland penalties, the first after Franco van der Merwe was penalised at a line-out and another when Ulster hands slowed ball at a ruck.
Another useful attack from the home side forced Van der Merwe offside as Priestland made it three out of three.
And it was 12-0 after 33 minutes as Priestland found the target again after Rory Best handled the ball at a ruck.
Priestland sent a 40-metre attempt wide and was short with another shot but an 11-3 penalty advantage at the break had already taken its toll.
But it took Ulster only 90 seconds after the restart to break their duck, with Marshall and Cave combining effectively twice for Cave to go in under the posts and Humphreys converting.
Scarlets had put themselves under pressure when Rhodri Williams' box kick had gone straight into touch from just outside the 22.
Priestland was wayward with another penalty after Ulster continued to struggle at the scrum. Ulster also had a chance to cut the deficit further but Humphreys was wide of the target with his first penalty shot on 55 minutes.
But Scarlets got on the scoreboard next with a Priestland penalty which went over via the help of the right upright to take the home side into a 15-7 lead on 61 minutes.
Referee Doyle lost his patience with the Ulster scrum and sin-binned tight-head prop Declan Fitzpatrick on 65 minutes.
But despite being down to 14 men Tommy Bowe broke through the Scarlets defence before Cave could not hold on to what would have been a try-scoring pass.
But Pienaar kicked two penalties, one from close to halfway, in the space of three minutes to cut the deficit to only two points.
However, on 76 minutes Pienaar missed a third penalty which would have given Ulster the lead.
And the contest but was put to bed two minutes from time when flanker Davies intercepted the ball from an Ulster scrum to go over under the posts. Priestland added a drop-goal conversion.
