Connacht's hopes of a prized defeat of their provincial rivals Leinster were blown apart by a disappointing final quarter-hour at the Sportsground.

The westerners faltered in the final straight as Leinster hit them with a 15-point salvo in as many minutes. The hosts, in front of their record crowd for a league fixture (3,678), had done well to close it up to 16 points apiece with Mark McHugh thumping over two penalties and local favourite Daniel Riordan hitting a third.

But even though they were forced to play with 13 men for a short while, with both prop Ronan McCormack and lock Malcolm O'Kelly in the sin bin, Leinster really clicked into gear to close out a four-try 31-16 victory.

Connacht, whose number 10 McHugh was yellow carded for a scuffle with McCormack, were left stunned as replacement centre Gordon D'Arcy pinged over a drop goal and Shane Horgan and Denis Hickie both cut through for injury-time tries, with Hickie's converted by Felipe Contepomi.

Having lost on six of their previous ten visits to the Sportsground, the win had an added value for Leinster.

After his side's second defeat in their last three outings, Connacht coach Michael Bradley said: "With ten minutes to go in the match, we were back level with them. We had a very good chance to win the game and obviously we're very disappointed not to have gotten anything out of it.

"We put a lot of pressure on Leinster and we were quite happy, with ten minutes to go, with the crowd behind us - it was a fabulous crowd and a great atmosphere - and we were putting a lot of pressure on Leinster.

"I think we just lost our composure at that point, and then Leinster got on top of us and got the couple of tries near the end.

"We lost our way and that is the disappointing aspect. We had spoken at half-time about maintaining our composure for the entire second half, but we only managed it for the 30 minutes or so.

"Still there were plenty of positives to take from the game and we will certainly build on them."

Connacht entertain title holders Ulster in Galway next Friday, while round six will also see Michael Cheika's Leinster side renew acquaintances with Munster, their Heineken Cup conquerors of last season, at Lansdowne Road.

Out west, Cheika gave credit to Connacht for their battling performance, insisting: "Connacht are going to beat a lot of teams down here. They are well structured - they tackle hard and they run hard. We always knew it was going to be a battle here."

Seeing his players find that extra gear in the final minutes was especially pleasing for the Australian coach.

"When Connacht got back level and we were down to 13 men for a time, I was pleased with the way we responded. I thought we changed our body language, kept the ball and then controlled the game to get those late scores.

"I was happy with the (international) players who were coming back in - a lot of the guys got back into the groove very quickly, and we made some good interchanges."