12 Dec, 14:42
Prop Cian Healy is expected to miss the start of the 2014 RBS 6 Nations after undergoing surgery on his injured ankle on Wednesday.
They sit proudly at the summit on 81 points, three ahead of closest rivals Leinster, who will be at home to third-placed Glasgow Warriors in the play-offs.
Mark Anscombe's men will host the Scarlets at their own fortress Ravenhill next Friday night (kick-off 7.45pm), on the back of their 17th win out of 22 league games this season.
Although ninth-placed Cardiff had little to play for on paper, it was quickly clear they had not made the trip to Belfast just to make up the numbers.
Centre Dafydd Hewitt picked off a fourth minute try after a fine central breakaway by scrum-half Lewis Jones. Rhys Patchell converted for the visitors, and although Pienaar immediately had the chance to claw three points back from 30 metres, a rare misfire from the Springbok left the score at 7-0..
Pienaar did better than atone for his miss moments later, however, picking up a ball dropped by Gavin Evans on the 22 and darting over the line virtually unopposed.
Moments after converting his own try, the versatile half-back then launched a searching kick into the corner for Trimble to chase, and a second try was only prevented by alert defending from the Blues as they scrambled the ball into touch.
The score remained level as Patchell and Pienaar traded penalties at the beginning of the second quarter, but a composed 28th minute drop goal from the visiting out-half, who clipped his kick over a second before several Ulstermen closed him down, edged his side back in front against the run of play.
Nevertheless, it was Ulster who continued to play the more inventive rugby as the first half came to an end.
Two promising raids in quick succession were only blighted by the ball just evading Tommy Bowe as he chased Jared Payne's kick to the corner, and a knock-on by Trimble as Ulster tried again just before the whistle.
Nick Williams, one of two Ulstermen named in the PRO Dream Team for this season, grabbed the bull by the horns as the second half got underway.
The big New Zealander picked up from an early scrum and displaying some of the trademark ball-carrying strength.
Paul Marshall then took over and showed good vision to find Trimble on the right wing with a long lofted pass and, still with plenty to do, Ulster's right winger powered his way through a handful of tackles to touch down just over the line.
Pienaar converted the 43rd minute score from a tight angle, and added two penalties moments later to give his side the advantage they deserved at 23-13.
With the Blues now floundering somewhat, Patchell missed a kickable penalty before a collision between two Cardiff defenders chasing the same Payne kick saw Trimble pounce on a loose ball and claim his second try of the evening, converted once more by Pienaar.
With Ulster pushing for the fourth try and their 11th bonus point of the season, Ireland internationals Paddy Jackson, Dan Tuohy and Tom Court all entered the fray followed by Mike Allen, Peter Nelson and Nigel Brady, who was greeted with a warm reception for his very last Ulster cap.
However, they all had to wait until the 78th minute to seal the bonus point, when the excellent Diack profited from a quick restart after the sin-binning of Hewitt to pick up metres from the line and drive over under the posts.
Pienaar added another conversion to his personal tally and with the match all but over, Tuohy narrowly failed to register a fifth try as Jackson's smart kick towards the corner just eluded him.
Ulster now have a week to prepare for their play-off clash with the Scarlets, who qualified in fourth place despite a heavy home defeat at the hands of Benetton Treviso this evening.
The province should go into the semi-final full of confidence, given that they have beaten the Llanelli-based outfit twice already this season, including a 47-17 romp at Ravenhill in January.
|Ulster Rugby Score Card|
|Cardiff Blues Score Card|