Leinster 59 Cardiff Blues 22:Leinster steamrolled Cardiff at the RDS this evening to move into fourth in the RaboDirect PRO12 with a polished nine-try performance, but an injury to Ireland captain Brian O'Driscoll will be a worry for Declan Kidney ahead of the autumn internationals.

The prognosis from Joe Schmidt after the game was that the sprained ankle was not "too serious" but the centre hobbled off in obvious discomfort in the first half.

“He was going to play on but in the end we measured up the responsibilities he has coming up and we decided to replace him," the coach told RTE.

Schmidt put his side's demolition of an abject Blues down to the extra day's rest his men have had this week, but Cardiff's problems were not just down to fatigue. The visitors failed in almost every aspect of their game, and Leinster showed no sympathy when running in six tries before the break to move into a 40-3 lead and wrap the bonus point up early.

Leinster had already gone over three times when O’Driscoll was forced off after 19 minutes. The homeside hardly missed him, as they racked up the quickest bonus point of this season after just 26 minutes.

Richardt Strauss, Ian Madigan, Jamie Heaslip and David Kearney all touched down to effectively seal the province’s five-point return, and Heaslip and Cian Healy added two more tries before the break.

Cardiff replied through a Leigh Halfpenny penalty and their Wales stars were otherwise anonymous until Alex Cuthbert, Halfpenny and Tom James finished off second-half tries. But the hosts managed to add three more tries to their tally, with Jordi Murphy and Damian Browne both touching down for the first time in Leinster colours and Fionn Carr added the ninth in the final minute.

The returning Kearney made an impact within three minutes, exposing some sloppy defending from the Blues as he blazed through midfield.

Gordon D’Arcy kept the move going and good footwork allowed Strauss to burrow over on the right, scoring a try to celebrate his first call-up to the Ireland squad earlier this week.

Jonny Sexton, who kicked 14 points, landed the first of his seven conversions and Leinster were in no mood to sit on their early lead as O’Driscoll evaded his Lions team-mate Jamie Roberts in the build-up to their second try.

Fergus McFadden cut in smartly off his wing and passed for supporting full-back Madigan to finish off to the left of the posts. Sexton converted for 14-0.

Cardiff clawed back three points through the boot of Halfpenny and James threatened soon after as the action quickly swung from end to end.

Leinster continued to look explosive in attack against a sluggish Cardiff defence. O’Driscoll was involved twice, getting the better of Roberts and Josh Navidi, before passing for Kevin McLaughlin to put Heaslip over on the left.

O’Driscoll damaged his left ankle during the move and received treatment while Sexton converted. Brendan Macken was sent on to replace the Ireland captain.

Leinster were unrelenting as Murphy and D’Arcy bulldozed through the attempted tackles and Sexton swung a long pass out for Kearney to slip in along the right touchline for the bonus-point score.

Sexton maintained his 100 per cent kicking record by adding the extras and with Cardiff losing prop Scott Andrews to the sin-bin, the visitors were soon standing behind their posts again.

From a close-in scrum, Leinster piled on the pressure and number eight Heaslip plunged over off the base for his second try. Sexton’s successful kick extended the margin to 32 points.

Prop Healy, making yards with every carry, then stretched past two defenders to claim Leinster’s sixth try with Sexton suffering his first miss.

The nightmare continued for Cardiff just 90 seconds into the second period as man-of-the-match Murphy, supported by replacement Browne, drove over for his try.

Sexton landed a superb conversion from the left before the Blues belatedly mounted a response, Cuthbert cutting through out wide for an unconverted effort.

Leinster rumbled forward ominously from the restart and a deft pass from Madigan released Browne for a simple run-in despite Navidi’s last-ditch challenge.

Sexton supplied the extras for 54-8 and Cardiff roused themselves for a late bonus-point push. Firstly, Jason Tovey looped a pass out for Halfpenny to touch down and convert.

Halfpenny added another seven-pointer with 11 minutes remaining, after Tom Williams’ kick forward bounced favourably for James to score again on the left.

Normal service was resumed late on though as Sexton dangled a kick over to the left where replacement Carr gathered, shipped a tackle and stretched over from a metre out.