London Irish (15) 25
Tries: Paice Cons: Homer Pens: Homer 6
Wasps (12) 12
Tries: Flutey, Webber Cons: Walder
Tom Homer kicked six penalties to take the game away from Wasps
London Irish boosted their hopes of a top-six finish as they came from behind to beat Wasps at the Madejski Stadium.
Early tries from Riki Flutey and Rob Webber saw the visitors storm into a 12-3 lead.
Exiles wing Tom Homer then took over, kicking six unanswered penalties as Wasps paid the price for indiscipline.
A try from Irish replacement David Paice early in the second half settled the outcome, with Wasps offering little in attack.
A home win for Irish had looked in doubt early on as Wasps' backs created scoring opportunities for both Flutey and Webber.
But the visitors failed to capitalise, instead giving away a string of penalties from which Homer made no mistake with the boot.
Adding to their woes was the departure of the lively Dominic Waldouck with a leg injury, replaced by the returning Josh Lewsey, who failed to make a lasting impression.
By the half-time whistle, Irish were in front, with five penalties from Homer giving them a 15-12 lead.
Homer continued where he left off after the break, kicking a sixth penalty after Andy Powell was penalised for holding on.
Wasps then enjoyed a brief resurgence in possession but were unable to create any significant holes in Irish's defence - and when Paice was sent over by Paul Hodgson with 25 minutes left, the home side moved 13 points clear.
The visitors kept pressing late on but were denied a way through by a resolute Irish side that are now fifth in the Premiership standings.
Wasps stay eighth, only one point above ninth-placed Exeter.
London Irish coach Toby Booth:
"We are delighted with the win. We are very difficult to beat at home.
"The play-off spot is not in our hands. We've relinquished control of that, but we must put our best foot forward.
"We've got to start winning on the road, beginning with Sale at the Reebok in a fortnight's time."
Wasps director of rugby Leon Holden:
"I thought it was going to be our day.
"Our defence and set-piece was very good and we played all the rugby in the first half and got no reward.
"I was disappointed with all the penalties but it was much more encouraging and we got stuck into our work a lot more."
London Irish: D. Armitage, Ojo, Seveali'i, Mapusua, Homer, Bowden, Hodgson, Dermody, Buckland, Rautenbach, Kennedy, G. Johnson, Gibson, S. Armitage, Stowers.
Sin Bin: G. Johnson (79).
Wasps: van Gisbergen, Wade, Waldouck, Flutey, Lemi, Walder, Simpson, Payne, Webber, Taulafo, Shaw, Veale, Hart, Ward-Smith, Powell.
Ref: Chris White (RFU).