The Blues got the better of Ulster for the second week running as they boosted their chances of featuring in next season's Heineken Cup and dented the home side's own European qualification hopes.

Dai Young's men are six points away from the Magners League's play-off zone, so they still have an outside chance of breaking into the top four before the end of the regulation phase.

Ulster, meanwhile, will now have to concentrate on finishing above Irish rivals Connacht in the table, with only four points now separating the sides in eighth and tenth places respectively.

Tries from man-of-the-match Casey Laulala, Ulster-bound Xavier Rush and Dafydd Hewitt, just three minutes after his introduction, saw Cardiff take the spoils, with place-kickers Leigh Halfpenny and Ceri Sweeney booting 18 points between them.

Ulster showed glimpses of what they can do with second half tries from back rowers Stephen Ferris and Chris Henry, but they were never quite close enough to threaten Cardiff's control of the scoreboard.

Out-half Niall O'Connor got Ulster moving with an early penalty from under the posts when Gethin Jenkins was pinged at a five-metre scrum after David Pollock had almost registered a morale-boosting opening try.

Scrum half Isaac Boss got the Ulster forwards firing with some pick-and-goes and they rumbled up towards the Cardiff posts, only for referee Andy Macpherson to get in the way as Pollock peeled off the side of a close range ruck.

It looked like the young Ulster flanker might have made it over the line under a pile of bodies, but play had to be called back and Cardiff got on top for the remainder of the first period.

Indeed, O'Connor's assured place-kicking was Ulster's only response as the Welsh region broke through for a brace of tries.

Laulala's score came shortly after Ulster's opening penalty when a pass from O'Connor was picked off by the centre who ran in unopposed from 60 metres out. Number 10 Ceri Sweeney converted the intercept and the Blues were on their way.

Halfpenny landed his first penalty eight minutes after Laulala's 10th-minute try and then just before the half hour mark, the young winger kicked a long range effort, after Ulster prop BJ Botha was penalised for dropping a scrum, which put the Blues clear at 13-3.

A penalty from O'Connor at least kept Ulster in touch, but only briefly as six minutes before half-time, number 8 Rush showed a good turn of pace to foil the Ulster cover and touch down under the posts after Boss failed to gather an up-and-under.

Sweeney added the extras to make it 20-6 for the visitors and even though O'Connor kicked his third penalty, it was Halfpenny who completed the opening half's scoring, landing another long range penalty for a 23-9 interval lead.

O'Connor cut the gap to 23-12 shortly after the restart and then Ferris smashed his way through tackles from Gareth Williams and Tom James before crashing past full-back Chris Czekaj for a barnstorming 51st minute score.

At 23-17 it looked as if Ulster might mount a realistic challenge but Halfpenny landed another penalty before just falling short from halfway.

Then, with 12 minutes remaining, the Blues showed good continuity following a powerful break from Jamie Roberts and replacement Hewitt danced his way past Botha to go in behind the posts. Halfpenny converted.

Ulster had most of the possession in the closing stages and pressure in the Cardiff 22 led to Henry dotting down in the left corner, with replacement Ian Humphreys cracking over a fine conversion from wide out.

But despite Ulster's renewed efforts, Cardiff were able to comfortably see out the win which marked their first success on Irish soil this season.

Speaking after the game, Blues prop Gethin Jenkins admitted: "It was a great win for us, the boys really put the effort in.

"We knew we had to come out here and put a good performance in to get our European spot, it's a step closer and I'm really chuffed with the win.

"A few early tries and some good defence throughout the game really helped us."