Defending champions Harlequins moved to the top of the English Premiership on Sunday after a fortuitous last-minute try from Tom Casson gave them a 31-28 win over London Irish.
Casson looked to have squandered the chance to score in the dying stages but the television official ruled that his apparent knock-on had actually come off his knee, rendering the try legal.
It was a cruel end to the game for the Exiles, who had seemed poised to record a precious victory thanks to a fine kicking display from Ian Humphreys.
Tries from Danny Care and Tom Williams had put Quins 26-19 in front with just over 20 minutes left, but Humphreys kicked the home side into the lead with three penalties before Casson's dramatic late intervention.
The victory allowed Quins to claim their first win in three Premiership matches, while Irish were brought down to earth after a sequence of three straight successes in all competitions.
In Sunday's other game, a brace of excellent tries from 20-year-old wing Christian Wade inspired Wasps to a 29-19 success over London Welsh at Adams Park.
Tom Varndell also impressed with two tries, but Wasps would have won by a far greater margin had Nicky Robinson not missed five of his six attempts with the boot.
Harlequins 31-28 London Irish
Pens: Humphreys 7
Tries: Williams, Care, Casson
Pens: Botica 4
London Irish: 15 Anthony Watson, 14 Topsy Ojo, 13 Jonathan Joseph, 12 Guy Armitage, 11 Sailosi Tagicakibau, 10 Ian Humphreys, 9 Tomás O'Leary, 8 Chris Hala'ufia 7 Jamie Gibson, 6 Declan Danaher (captain), 5 Matt Garvey, 4 Bryn Evans, 3 Halani Aulika, 2 David Paice, 1 Max Lahiff.
Replacements: 16 Scott Lawson, 17 Cai Griffiths, 18 Leo Halavatau, 19 Kieran Low, 20 Ofisa Treviranus, 21 Alex Gray, 22 Steven Shingler, 23 Darren Allinson.
Harlequins: 15 Mike Brown, 14 Tom Williams, 13 Matt Hopper, 12 Tom Casson, 11 Ugo Monye, 10 Ben Botica, 9 Danny Care, 8 Nick Easter, 7 Chris Robshaw (captain), 6 Tom Guest, 5 George Robson, 4 Olly Kohn, 3 James Johnston, 2 Rob Buchanan, 1 Joe Marler.
Replacements: 16 Dave Ward, 17 Mark Lambert, 18 Will Collier, 19 Charlie Matthews, 20 Maurie Fa'asavalu, 21 Karl Dickson, 22 Rory Clegg, 23 Seb Stegmann.
Referee: Tim Wigglesworth
Assistant referees: Stuart Terheege, Roy Maybank
TMO: Graham Hughes
London Wasps 29-19 London Welsh
For London Wasps:
Tries: Wade 2, Varndell 2
Pens: Robinson, Thomas
For London Welsh:
Tries: Mackenzie, Montanella
Pens: Henson 2, Ross
London Wasps: 15 Hugo Southwell, 14 Tom Varndell, 13 Andrea Masi, 12 Lee Thomas, 11 Christian Wade, 10 Nick Robinson, 9 Joe Simpson, 8 Billy Vunipola, 7 James Haskell, 6 Ashley Johnson, 5 Marco Wentzel, 4 Joe Launchbury, 3 Zak Taulafo, 2 Tom Lindsay, 1 Tim Payne.
Replacements: 16 T Rhys Thomas, 17 Phil Swainston, 18 Fabio Staibano, 19 James Cannon, 20 Jonathan Poff, 21 Charlie Davies, 22 Tommy Bell, 23 Elliot Daly.
London Welsh: 15 Tom Voyce, 14 Phil MacKenzie, 13 Sonny Parker, 12 Seb Jewell, 11 Nick Scott, 10 Gavin Henson, 9 Tyson Keats, 8 Ed Jackson, 7 Michael Hills, 6 Jonathan Mills (captain), 5 Matt Corker, 4 Martin Purdy, 3 Paulica Ion, 2 Neil Briggs, 1 Franck Montanella.
Replacements: 16 Dan George, 17 Tom Bristow, 18 Arthur Joly, 19 Kirill Kulemin, 20 Alfie To'oala, 21 Nick Runciman, 22 James Lewis, 23. Joe Ajuwa.
Referee: Nigel Owens (Wales)
Assistant referees: Nigel Carrick, Andrew Watson