Last year's beaten finalist virtually ruled themselves out of contention for a place in the knockout stages after falling to improving Belfast Harlequins.

Harlequins were almost left to rue letting an early lead slip but one Lansdowne score in the second half told its own tale.

Lansdowne outhalf David Quigley had turned in a masterful display from the boot kicking three penalties and a drop goal to bring his team back into contention. But without Leinster and Irish centre Shane Horgan Lansdowne looked less than assured behind the scrum.

Harlequins were always the more inventive. David Spence's incisive break saw him steal clear of the home side's cover for Harlequin's opening try on nine minutes. Spence then launched a teasing kick behind the Lansdowne defence with Ross Collins touching down.

Lansdowne's pack then started to take over with the assured left boot of David Quigley seeing Harlequin's lead wiped out by the interval.

The second half belonged to Harlequins with Paul Hancock restoring the lead on 51 minutes. And then on the hour mark, Robin Morrow went over for their second try. Shane Whelan grabbed a consolation score for Lansdowne in the dying seconds.

Lansdowne: G D'Arcy; L O' Brien, P Berry, G Hamilton, R Niland; D Quigley, S Whelan; R Corrigan, O Ennis, E Bohan, S O'Connor, G Quinn, S Rooney, G Molloy, C McEntee. Replacements: A McKeen for Corrigan (69 mins), R Geraghty for O'Connor (69 mins), R Dolan for O'Brien (65 mins).

Belfast Harlequins: N Malone; R Collins, S Coulter, S Dick, R Morrow; P Hancock, D Spence; C Keown, M Humphries, S Best, K Rabie, D Irwin, C Galwey, N Best, G O'Loan. Replacements: D Scott for Keon, C McCarey for Galwey (52 mins), N McBride for Morrow (70 mins).

Referee: J Sheehan (MRA).