England captain Lawrence Dallaglio put Wasps one win away from Twickenham by scoring the only try of a punishing quarter-final at Loftus Road.

Dallaglio struck seven minutes from time after back-row replacement Eben Rollitt unlocked a previously watertight Irish defence.

Roared on by a record crowd of more than 11,000, Wasps finally made incessant second-half pressure count through a late, 10-point scoring burst.

The outstanding Dallaglio started it, wing Kenny Logan converted the try and then completed his penalty hat-trick as Wasps stayed on course for a second successive final appearance.

Dallaglio was in prime form just six days before England's difficult Five Nations Championship mission against Ireland at Lansdowne Road, bouncing back superbly from his personal disappointment at the way England played in their narrow win over Scotland.

The Wasps' pack responded to Dallaglio's stirring example, gaining an early second half foothold in Irish territory, and then scarcely relinquishing it.

A bitter, gusting wind made conditions difficult, and Irish just could not break out.

To complete a disappointing afternoon for the Exiles, they lost Ireland wing Justin Bishop with a leg injury on the stroke of half time.

Logan, off target for Scotland at Twickenham eight days ago, struck his opening penalty on 50 seconds when Irish infringed at the game's first ruck.

Irish took a while to establish any rhythm, but from their first real sortie into the Wasps 22 wing Niall Woods stroked an angled penalty.

Both teams were intent on tackling each other to a standstill, and it took replacement Gareth Rees' 44th-minute drop goal from 30 metres to break the deadlock.

Inspired by Rees' nonchalant effort, the Wasps forwards went up a gear and Irish were never able to release their dangerous counter-attackers, Woods and full back Conor O'Shea.

Logan landed another penalty on 55 minutes, and, with tackling demons Rob Henderson and Trevor Leota knocking Irish backwards, the home side established a healthy dominance.

As the tie entered its closing stages, Irish simply could not hold out for any longer and Rollitt slipped through a tackle to send Dallaglio galloping across.

Logan converted from wide out before booting a 48-metre penalty, and Irish were finished even though scrum-half Kevin Putt launched a series of late raids in search of a consolation score.