Cardiff Blues surged to the top of the Magners Celtic League with a 31-20 bonus point win over the the Dragons at the Arms Park.
The result leaves them two points clear of Leinster, with the Irish province ending the season at the Arms Park on Friday week.
But the title favourites are still the Ospreys, now four points adrift, but with a game in hand on 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.
Blues 31 (17)
Tries: Phillips (2), Rush, Shanklin
Cons: Blair (4)
Pens: Blair
Dragons 20 (3)
Tries: Bearman, Maule
Cons: Sweeney (2)
Pens: Sweeney (2)
Blues: Ben Blair; Rhys Williams, Tom Shanklin, Marc Stcherbina, Chris Czekaj; Nicky Robinson, Mike Phillips; Gethin Jenkins, Gareth Williams, Gary Powell, Deiniol Jones, Robert Sidoli, Scott Morgan, Robin Sowden-Taylor, Xavier Rush (c).
Replacements: Scott Roberts, T Rhys Thomas, Bradley Davies, Mark Lewis, Martyn Williams, Wayne Evans, Jamie Robinson.
Dragons: Kevin Morgan (c); Gareth Wyatt, Gareth Maule, Phil Dolman, Richard Fussell; Ceri Sweeney, Gareth Cooper; Dai Maddocks, Ben Daly, Rhys Thomas, Andrew Hall, Luke Charteris, Joe Bearman, Jamie Ringer, Michael Owen.
Replacements: Adam Black, Dan Lydiatt, Ian Gough, Richard Wilkes, Martin Thomas, Aled Thomas, Alex Walker.
Referee: Nigel Owens (WRFU).