Holders Northampton saw their chances of defending their Heineken Cup title disintegrate in Donnybrook as Leinester completed back-to-back victories over them.

Following last weekend's Pool One win at Franklin's Gardens, tonight's was a most unlikely triumph because the European champions - needing victory to keep alive their slim hopes of retaining the Cup - dominated the early proceedings and led by18 points inside the opening 19 minutes.

By then Grant Seely and Allan Bateman had gone over for tries, one of them converted by fly-half Alastair Hepher who also dropped a goal.

But Leinster regained 10 points inside six minutes.

Their opening try came from left wing Gordon D'Arcy, and it was converted by fly-half Eddie Hekenui while centre Shane Horgan dropped a goal.

Four minutes before half-time Northampton increased their lead when lock Jon Phillips got in for a try again converted by Hepher.

However, Leinster had the last word of the first half when international right-wing Dennis Hickie broke from defence to chip a kick ahead and score beside the posts with Hekenui adding the points to leave Northampton leading by 25-17 at the break.

Hat-trick

Hepher increased that lead five minutes into the second period with a second penalty goal.

But after that it was all Leinster as D'Arcy scored twice to chalk up a hat-trick of tries, both his second and third converted by Hekenui who also knocked over a penalty goal.

With 10 minutes left Hepher landed another penalty goal for Northampton, but that was to be the last hurrah for the holders.

Hekenui landed two late penalty goals for Leinster to give them a victory.

Encouraging

"Our guys played with tremendous conviction having made a very bad start," said Leinster's coach Matt Williams.

"Admittedly Northampton's cause was not helped when their flanker Budge Pountney was sent off early in the match.

"But it has come to the point where the Irish teams are no longer overawed when up against English or French competition," said Williams.

"This was an encouraging win for us, and I have every hope that the team will go on even further."

While Northampton are left to rue their fate - they can no longer qualify from the group - Leinster would secure their qualification to the next stage with victory over edinburgh Reivers in their next match.