London Irish gave their survival hopes a massive boost with a superb 30-19 triumph over play-off chasing London Wasps.
Irish opened up an early 11-3 lead through Shane Geraghty's try and two Tom Homer penalties before the visitors hit back via the boot of Stephen Jones and Christian Wade's touchdown.
Homer reduced the advantage at half-time to 16-14, but Jones gave Wasps a five-point lead in the second period. However, Marland Yarde's score and 11 more points from the Exiles' full-back gained a vital victory.
Despite an improvement in their performances recently, the hosts were facing the Premiership's in-form side who had won five matches in succession in the Premiership.
But that didn't deter Brian Smith's men and they dominated the opening exchanges with their forwards and half-backs controlling proceedings.
Homer duly opened the scoring after three minutes and added to his tally soon after as Irish took a 6-0 lead.
Although Jones responded for the visitors, it was the Reading-based outfit that crossed for the game's first try.
They received a penalty in front of the posts but, instead of taking the kick, the ball was shifted wide to Geraghty who touched down.
However, Wasps started to apply the pressure and the Exiles began to concede penalties. Successive three-pointers by their fly-half reduced the deficit to 11-9 before Wade brilliantly finished off a well-worked try.
Homer took the score to 16-14 just before the interval, but Jones immediately cancelled it out in the second half after Chris Hala'ufia had been sin-binned.
But another from the boot of the hosts' full-back kept them in contention and Yarde's superb try regained Irish's lead. And it was Homer who sealed the win two further penalties.
For London Irish:
Tries: Geraghty, Yarde
Pens: Homer 6
For London Wasps
Cons: SM Jones
Pens: SM Jones 4
London Irish: 15 Tom Homer, 14 Topsy Ojo, 13 Guy Armitage, 12 Shane Geraghty, 11 Marland Yarde, 10 Ian Humphreys, 9 Pat Phibbs, 8 Chris Hala'ufia, 7 Ofisa Treviranus, 6 Matt Garvey,5 Bryn Evans (c), 4 George Skivington, 3 Halani Aulika, 2 Scott Lawson, 1 Max Lahiff.
Replacements: 16 Davy McGregor, 17 Jerry Yanuyanutawa, 18 Leo Halavatau, 19 Kieran Low, 20 Jamie Gibson, 21 Jon Fisher, 22 Sailosi Tagicakibau, 23 Jack Moates.
London Wasps: 15 Hugo Southwell, 14 Christian Wade, 13 Elliot Daly, 12 Chris Bell, 11 Tom Varndell, 10 Stephen Jones, 9 Joe Simpson, 8 Sam Jones, 7 Jonathan Poff, 6 Ashley Johnson, 5 Marco Wentzel, 4 James Cannon, 3 Will Taylor, 2 T Rhys Thomas, 1 Zak Taulafo.
Replacements: 16 Tom Lindsay, 17 Simon McIntyre, 18 Lorenzo Romano, 19 Alex Rae, 20 Matt Everard, 21 Charlie Davies, 22 Nick Robinson, 23 Charlie Hayter.
Referee: Tim Wigglesworth
Assistant referees: Ian Tempest, Andrew Watson
Timekeeper: Roy Marfleet
Television match official: David Grashoff
Assessor: Ashley Reay