Alex King kicked Wasps to a narrow 36-32 victory over Ulster which put a dent in the Irish side's Heineken Cup dreams in pool two at Loftus Road on Sunday.
King kicked five penalties and three conversions as Wasps - already out of the competition - avenged October's 42-19 humiliation in Ireland.
With only a minute played Ulster opened the scoring with a long-range penalty from fly-half David Humphreys but two minutes later his opposite number King levelled the scores with a penalty from 22 metres.
Fired-up Ulster relied heavily on Humphreys and in the eighth minute his penalty attempt sailed to the right of the upright, although he made amends seven minutes later with a powerful penalty from 30 metres.
Wasps, depleted by injuries but looking dangerous, made the breakthrough in the 16th minute with captain Mark Denney scoring a try on the right, converted by King.
Humphreys as taken off injured shortly after seeing a long-range penalty land in the arms of Wasps hooker Trevor Leota.
However, full-back Paddy Wallace had better luck after 22 minutes, pulling the Irish back into contention.
The scores did not stay close for long though as King slammed through a close-range penalty in the 24th minute.
Putting the Londoners further ahead in the 30th minute King sent through another successful penalty.
After a running the length of the pitch, Wasps winger Shane Roiser collected the ball in the 33rd minute and crashed over for a try, converted by King.
And King increased Wasps' advantage with his fourth penalty of the afternoon in the 40th minute. But in first-half injury time Wallace kicked a penalty to cut the half-time deficit to 26-12.
Centre Fraser Waters extended Wasps' lead when he intercepted a Wallace pass to touch down, with King converting.
A determined Wallace lobbed through his third penalty of the afternoon in the 53rd minute.
Ulster broke down the left in the 57th minute with Ulster skipper Andy Ward claiming a try and Wallace converting as the Irish desperately looked for a way back into the match.
In the 63rd minute Ulster charged down the field with Ryan Constable taking on the try-scoring duties, leaving Wallace to convert and close the gap to just four points.
The home side were reduced to 14 men following the sin-binning of lock Ian Jones in the 70th minute and a minute later Wallace scored a drop goal.
But two minutes from time King secured victory for the English side, slotting home a short-range penalty.
Teams:
Wasps: Leek, Roiser, Waters, Denney, Roberts, A. King, Wood, Dowd, Leota, W. Green, Shaw, Jones, Beardshaw, Volley, Lock.
Replacements: Mackenzie for Shaw (75).
Not Used: Burrill, Barratt, Scrase, Allen, S. Green.
Sin Bin: Jones (70).
Tries: Denney, Roiser, Waters.
Cons: A. King 3.
Pens: A. King 5.
Ulster: Wallace, Coulter, Larkin, J. Bell, Howe, Humphreys, Doak, Fitzpatrick, Shields, Best, Johns, Longwell, McWhirter, Ward, Nelson.
Replacements: Constable for Larkin (53), B. Cunningham for Humphreys (40), Crick for Shields (62), Davidson for Longwell (53), McMillen for McWhirter (59).
Not Used: K. Campbell, Boyd.
Tries: Ward, Constable.
Cons: Wallace 2.
Pens: Humphreys 2, Wallace 3.
Drop Goals: Wallace.
Att: 5,959
Ref: G Morandin (Italy).