Defeat by Cardiff Blues in a Millennium Stadium thriller every bit the equal of the previous day’s FA Cup final completed a whitewash by the four Welsh regions.
Not that the Celtic League record 15,327 who packed the stadium’s middle tier were complaining after a feast of rugby.
The Blues took the lead with their first attack, thanks to some courageous ball-winning by Robin Sowden-Taylor.
Jamie Robinson was involved twice and, after Mike Phillips was held up just short, Nick Macleod grabbed the ball and rolled over to touch down.
Fly half Nicky Robinson slotted over two penalties before Leinster struck back with an opportunist score by Shane Horgan after a Phillips clearance was charged down. Felipe Contepomi converted.
But the Blues scrum-half, back at the scene of his man-of-the-match display for Wales against France, made amends for his error with a brilliant individual try, a trademark sniping break sending him under the posts to give Robinson an easy conversion.
It was back to Phillips the villain, however, when his failure to clear a bouncing ball allowed Gordon D’Arcy in and Contepomi added the conversion to an earlier penalty.
Blues wing Chris Czekaj, close to a try just before the break, raced in to open the second-half scoring following an outrageous dummy by Marc Stcherbina, but superb hands by Leinster skipper Contepomi brought an immediate response from Denis Hickie.
Just to show this was not simply an end-of-season frolic, Blues prop John Yapp and Leinster lock Mal O’Kelly indulged in a bout of fisticuffs which saw both sin-binned.
A Robinson penalty extended the Blues’ lead, but replacement Rob Kearney put the visitors in front for the first time, pouncing on a kick-ahead by Contepomi and claiming a vital bonus point in the process.
But Blues had their own supersub, Martyn Williams, who grabbed his side’s fourth try and restored their lead, Robinson adding the extras.
And Craig Morgan, who leaves for Bristol in the summer, celebrated his 100th Cardiff appearance with the final try of a magnificent game.
: Tries: Macleod, M. Phillips, Czekaj, M. Williams, Morgan. Cons: N. Robinson 3. Pens: N. Robinson 3.
: Macleod, Czekaj J. Robinson, Stcherbina, Morgan, N. Robinson, M. Phillips, Yapp, R. Thomas, Jenkins, D. Jones, Sidoli, Molitika, Sowden-Taylor, Rush.
: R. Powell for M. Phillips (79), Schubert for D. Jones (40), M. Williams for Molitika (67).
: Tries: Horgan, D’Arcy, Hickie, Kearney. Cons: Contepomi 4. Pens: Contepomi.
: Dempsey, Horgan, D’Arcy, Lewis, Hickie, Contepomi, Easterby, Corrigan, Jackman, Byrne, Byrnes, O’Kelly, Miller, Gleeson, Heaslip.
: Kearney for Lewis (64), Blamey for Jackman (40), Green for Byrne (40), Ronan for Miller (15).
: R Dixon (Scotland).