Leinster find themselves in the unfamiliar position of playing Celtic League catch-up after Cardiff's 31-20 win over the Dragons propelled the Welsh side the top of the table.

Cardiff, who meet Leinster on the final day of the season, moved two points clear thanks to their four-try (which secured a bonus point) win at the Arms Park and, with just two games remaining, the title is now their's to lose.

But the Ospreys remain very much in contention as while they are  now four points adrift, they have a game in hand on Leinster and their fellow Welshmen.

The Dragons, with the evening sun behind them, applied the early pressure, but a handling error allowed the Blues to take the lead. Outstanding scrum-half Mike Phillips snatched up a loose ball near the centre spot, broke a tackle and raced under the posts for Ben Blair to convert.

Visiting fly-half Ceri Sweeney, who had looked bemused when an earlier penalty was adjudged to have curled wide, made no mistake with a second attempt after the Blues strayed offside.

Blair cancelled it out with a penalty of his own after the Blues had pushed the Dragons off the ball at a scrum and their forward power proved decisive in their second try.

The Dragons survived a driving line-out, but only at the expense of a yellow card for flanker Jamie Ringer - his second in four days - and when the Blues opted for a scrum instead of a kick an inside pass from Phillips sent number eight Xavier Rush over, and Blair added the extras.

Dragons coach Paul Turner had promised they would be party-poopers and they showed their mettle in the opening minutes of the second period with a Sweeney break allowing dangerous winger Richard Fussell to send flanker Joe Bearman in for Sweeney to add the extras.

But another Phillips gallop from a Blues turnover saw him combine with Robin Sowden-Taylor for Tom Shanklin to run a superb angle and score. Blair's kick restored the 14-point margin.

A Sweeney penalty kept the Dragons interested, but the Blues secured their bonus point when Phillips wriggled his way over, the try being awarded on the say-so of a touch judge. Blair again converted.

A 70-yard breakaway try by centre Gareth Maule, improved by Sweeney, caused a few flutters among the more nervous members of the 9,326 crowd, but the Blues were able to hold out without further difficulty.