It was top against bottom in Dublin and it became all too obvious during the second half that Leinster are the team left fighting for some silverware this season.

Ulster, still with caretaker coach Steve Williams at the helm, put in a brave effort. They defended tigerishly throughout and the fact that it took the home side 57 minutes to break the try deadlock spoke volumes about Ulster's will to get something out of the game.

But not much came off for them in attack and when it did, most notably through the likes of Andrew Trimble, Ryan Caldwell and Bryn Cunningham, Leinster still managed to regroup and stop them from getting a sight of the whitewash.

Michael Cheika's side were without the services of injured duo Brian O'Driscoll and Shane Horgan and suffered an early set back when South African prop Ollie Le Roux was forced off with a rib injury.

Leinster kept the ball with their forwards for long stretches of the first half, battering away at the Ulster defence and trying to take their dominance at scrum time into the loose.

After an early wave of attacks, Ulster infringed, allowing Felipe Contepomi to kick Leinster in front.

With O'Driscoll sidelined, the Argentinian star joined Gordon D'Arcy in the hosts' midfield, allowing young Jonathan Sexton to slot in at number 10 and the former Ireland Under-21's line-kicking and directing of play was impressive.

Both sides had their moments in attack during the first half. Contepomi combined with Sexton and flanker Keith Gleeson for a flowing move that had the Ulster defence under pressure.

Ulster centre Trimble was unfortunate not to hold onto a 24th-minute pass - had he done so, his pace make have taken him all the way to the Leinster try-line.

Gleeson also had to produce a top quality tackle to halt Trimble's progress as he threatened to break through the cover.

But a subsequent ruck infringement allowed Contepomi to double Leinster's lead and he kept up his 100% kicking record in the 29th-minute, after Ulster scrum half Isaac Boss had been sin-binned for persistent ruck infringing.

Turning around at half-time with a 9-0 deficit, Ulster missed a good chance to reply when Paddy Wallace, who started ahead of the fit-again David Humphreys, failed to get enough weight behind a right-sided penalty kick.

After Ulster lost flanker Neil Best to the sin-bin for a foot trip on Sexton, Leinster put the result beyond doubt. Contepomi swung over his fourth and fifth penalties and in between those strikes, replacement prop Cian Healy stepped and sped his way over from close range for the opening try.

Contepomi made it a seven-pointer and he also added the extras to Jamie Heaslip's excellent 68th-minute score. A well-timed pass from Sexton put the Ireland-capped number 8 haring through a gap and he had the pace to dash in behind the posts for a memorable try.

The result, which sees Ulster remain winless in Dublin since 1999, keeps Leinster at the top of the standings and gets them back on track after their recent Heineken Cup collapse to Edinburgh.

Replacement Humphreys dubbed this loss "probably the lowest point" of Ulster's season to date. The province remain bottom of the table but will hope that Ravenhill can provide them with some home comfort against Munster on Friday week.