Fourteen-man Leinster were crowned Celtic League champions when they beat their arch-rivals Munster 24-20 in the inaugural final at Lansdowne Road.

Matt Williams' side came from behind and having been reduced to 14 men following the 25th minute dismissal of flanker Eric Miller.

They trailed 12-6 at half time after Munster had touched down twice through Anthony Foley and John O'Neill but hit back with second-half tries from Gordon D'Arcy and man of the match Shane Horgan.

Munster coach Declan Kidney had had his preparations ruined by injuries to key players.

First choice scrum half Peter Stringer was a late withdrawal with an ankle injury and joined internationals John Hayes and David Wallace in the stands.

But Kidney sprung a surprise when he named a supposedly injured centre, Rob Henderson, in his starting line-up alongside John Kelly and left out established midfield pairing Jason Holland and Mike Mullins.

The game itself was packed with incident from the first minute when Leinster's Nathan Spooner missed a penalty and Munster had to bring off full back Dominic Crotty with a cut to his head.

Munster were quickly in control however when in the fifth minute they drove towards the goalline.

After several attempts the Leinster defence was unlocked and number eight Foley piled across the line to score under the posts. Ronan O'Gara converted and Munster were 7-0 in front.

Crotty returned to the fray with his head bandaged as Spooner put Leinster on the scoreboard with a penalty in front of the posts. And it was Crotty who made a last-ditch tackle in the 22nd minute to prevent Shane Horgan bursting through having already beaten other Munster tackles.

A minute later Munster scrum half Mike Prendergast was sin-binned for stray hands in the ruck and Spooner sent over his second penalty.

The game ignited in the 25th minute when Leinster back row Miller was sent off by Welsh referee Nigel Whitehouse for kicking Kelly and, as he headed for the dressing rooms, O'Gara missed a penalty in front of the posts.

The scores stayed at 6-7 until just before half-time when Munster advanced up the left before O'Gara switched play to the right. Three phases later and O'Gara's long pass found wing O'Neill in the corner for Munster's second try. O'Gara missed a conversion and Munster went in 12-6 at half-time.

The second half began with O'Gara and Spooner exchanging penalties to bring the scores to 15-9. Spooner missed another penalty in the 53rd minute but made amends in the 65th minute.

Crotty was forced to give way to Mullins once again and the stand-in fullback was soon under pressure. He fumbled a catch but recovered only to kick straight down Leinster wing Denis Hickie's throat.

Hickie charged into Munster territory from where Shane Horgan broke through and off-loaded to D'Arcy who touched down in the corner. Leinster were in front for the first time and Spooner converted to make it 19-15.

With 10 minutes to go Leinster scored a barnstorming try that ultimately sealed the game.

Spooner made a break and fed Brian O'Driscoll who kicked ahead only to be dragged down by O'Neill as he chased. The referee played the advantage and Leinster were rewarded when Shane Horgan touched down in the corner.

Spooner missed the conversion and although Anthony Horgan grabbed an injury time try for Munster, Leinster had done enough to beat their old foes first time in six matches and score their 14th consecutive win of this season.