London Welsh 15, London Wasps 34
London Welsh will go into 2013 nine points clear of the relegation zone after a record-breaking match at Oxford’s Kassam Stadium.
On the field, Welsh led 12-6 at the break, but had no real answer to Wasps' second-half surge.
This saw them end a 14-month streak without a top-flight away win and climb to fifth.
Off the field, however, a crowd of 10,045 was a home Premiership best for the Exiles, surpassing the 6,850 that watched the Leicester match.
Coming on a day of miserable weather, such a big attendance bodes well for Welsh, who hope to move their training base to Oxford next season.
With Sale having beaten Worcester on Friday night, the Exiles saw their buffer at the bottom cut to nine points over the weekend.
But this is certainly a position they would have taken before the season started.
Wasps only just avoided relegation last season, but are now looking a very accomplished side.
They included rising England star Joe Launchbury at lock and former Chinnor junior Tom Varndell on the wing.
On the bench, they had another Chinnor product in back-row forward Sam Jones.
England Under 20 star Elliot Daly was well short with a second-minute penalty for the visitors. But Welsh fly half Gordon Ross was spot on after his forwards won a penalty at the scrum – an area in which they excelled.
Wasps almost hit back immediately, but home full back Tom Arscott did brilliantly to scragg Varndell at full tilt.
And the hosts took full advantage with Ross’s second penalty making it 6-0 on 14 minutes. Wasps’ fly half Nick Robinson replied in kind soon afterwards and equalised on 21 minutes as his side found their feet.
Ross made it three penalties from three in his side’s next attack, but Robinson sliced his third attempt wide.
Try-scoring chances were at a premium, but another Robinson miss meant Welsh still led 9-6. The Exiles’ scrum looked good and forced a penalty in front of the posts, which Ross converted for a 12-6 half-time lead.
Robinson landed a well-struck penalty shortly after the break as his side upped the ante.
When Wasps broke through, it was a real beauty as England scrum half Joe Simpson accelerated through the middle and slipped a couple of tackles before having just enough momentum to get over.
Welsh will feel they should have stopped the fleet-footed No 9, but he proved just too slippery on a wet pitch.
Wasps soon led 17-12 after Daly landed a penalty from his own half.
Simpson threatened a second try when he collected a loose ball and scampered clear, but Arscott covered superbly down the touchline before running clear.
Ross missed a fairly easy penalty on 57 minutes, but Welsh were still in it.
Wasps, however, led 22-12 ten minutes later when Daly did brilliantly to squeeze over in the right corner from flanker Ashley Johnson’s pass.
The Welsh scrum gave them hope again, forcing another penalty, which Ross converted to trail 22-15.
But it was a different set-piece – the lineout – which cost the hosts decisively.
A mix-up saw the ball bounce for the marauding Johnson to collect and some good off-loading ended in prop Will Taylor going over and fellow replacement Stephen Jones converting.
With time running out, Welsh had to go for broke as they needed a converted try to gain anything from the match.
This led to Wasps scoring a fourth try from Varndell on the final whistle after Daly’s basketball-style pass.
Wasps deserved victory, but the scoreline was a little harsh on Welsh, who again battled hard.
London Welsh: Arscott, Caprice, Parker, Jewell, Scott, Ross, R Lewis (Runciman 60), Montanella (Bristow 69), Briggs, Tideswell, Mills (capt), Kulemin (Corker 57), Jackson, Denbee (Bateman 69), To’oala (Balding 51). Reps not used: Evans, Davies, J Lewis.
London Wasps: Southwell (capt), Varndell, Masi (Mayor 41), Bell, Daly, Robinson (Steve Jones 58), Simpson (Davies 73), Taulafo (Payne 66), Thomas (Lindsay 53-55 & 66), Swainston (Taylor 73), Launchbury, Cannon (Wentzel 66), Johnson, Poff (Sam Jones 55), Vunipola.
Referee: T Wigglesworth (Hull).