Victory for the Irish challengers would leave Wasps - European champions in 2004 and 2007 - needing a miracle to reach the quarter-finals.

Leinster know an away win should be enough for top spot in Pool Two, with tomorrow's rematch coming just three months after they walloped Wasps 41-11 in Dublin.

"This is the big one," said Leinster's Ireland international full-back Dempsey.

"It has been made all the bigger after our slip-up at Castres in round four. Along with Wasps beating Edinburgh, it really opened up the pool.

"It makes this our make-or-break pool game, and as Twickenham is such a special ground, we just hope the game lives up to its billing.

"We have plenty of big-match experience, playing at some of the biggest grounds in the world.

"The players certainly will not be daunted by either the size of the ground or the crowd. Playing at Twickenham will only inspire us."

Leinster posted six tries in running Wasps ragged during the second round of pool fixtures, although the Londoners have won 70% of their games in all competitions since then.

Dempsey added: "We will not be dwelling on the last game against Wasps - we will treat this as an entirely fresh game.

"Wasps are now a totally different side to the one we played in October.

"They have recently hit some good form, and when they do that and their confidence is up, they are a very difficult side to beat."