A last-gasp try from Sam Smith saw Harlequins record a fortunate 11-10 victory over London rivals Wasps.
For much of the match Wasps were the better side and it was not until Smith's late effort that the Quins troubled the try line.
They were lethargic and had to rely on penalties from Nick Evans and Ben Botica for the remainder of their points.
The Quins badly missed the spark of their absent England contingent and only the lively Karl Dickson could take much credit from a poor team performance.
Wasps were less hit by international call-ups but were still missing the injured Christian Wade and Hugo Southwell.
They will wonder how they failed to win the match as their pack was the dominant force in the match with young prop Jake Cooper-Woolley being the stand-out performer.
The visitors failed to take advantage of their total superiority in the first half and ultimately it cost them the match. Their pack were rewarded with a penalty try which was converted by Joe Carlisle who also added a penalty.
Both sides were forced to make late changes. George Robson's hamstring problem kept him out of the Quins line-up while Andy Goode was an absentee for Wasps with a knee injury.
Wasps, playing with the advantage of a strong wind, took a fourth-minute lead when Carlisle kicked a penalty but this was soon cancelled out with one from Evans.
The visitors suffered an early blow when they lost Ashley Johnson with a facial injury after only eight minutes, when he was temporarily replaced by Guy Thompson.
Wasps nearly opened their try-scoring account with a neat move.
Carlisle made a half break to send Cooper-Woolley into space; the prop fed Sam Jones who looked a likely scorer until he was hauled down by an excellent cover tackle from Dickson.
Wasps dominated the opening quarter and should have taken the lead but Carlisle missed a straightforward penalty attempt to leave it at 3-3 after 20 minutes.
However, they received a boost when influential flanker Johnson returned after treatment.
With half an hour gone, the Quins had managed to get into the opposition half on only one occasion and it came as no surprise when the visitors scored the first try.
The Wasps' pack battered the home line with a succession of line-out drives before a set scrum saw Wasps awarded a penalty try, which Carlisle converted.
It was therefore 10-3 at the interval and the Quins must have been mightily relieved that they were not further behind.
Within two minutes of the restart, the Quins suffered a setback when Evans left the field with a leg injury to be replaced by Botica, whose first action was to fire wide with a poor penalty attempt.
Botica had better luck with his second chance to reduce the arrears to four points. This was the prelude for the Quins to have the first sustained period of pressure.
A tricky run from scrum half Dickson caused the visitors' defence a momentary scare but the Quins lost three consecutive line-outs which prevented them from further building their momentum.
Wasps resumed control of the match and looked likely to hang on for a noteworthy win but, with two minutes to go, the Quins rose from their slumber to score the match-winning try.
They hammered the Wasps line before working the ball wide to Smith. The wing did brilliantly to force his way over to have his try confirmed after a lengthy deliberation by the T.M.O.