Wasps (13) 21
penalty, Barnard Con:
London Irish (6) 16
Sunday's match at Adams Park was a keenly-fought contest
Wasps kept their play-off hopes alive with a hard-fought victory over out-of-form London Irish at Adams Park.
The defending champions went behind to an early penalty but had a penalty try when Irish struggled at scrum time.
Fly-half Danny Cipriani increased the lead with two penalties but that was matched by Shane Geraghty.
A try for Pat Barnard and a Cipriani penalty put Wasps 21-9 ahead and although Adam Thompstone's try set up a tense finish, the home side hung on.
The victory is Wasps's fourth in five games as they recover from a dismal start to the season.
And although they are 14 points off the all-important play-offs, Ian McGeechan's men still believe they can repeat their traditional late-season charge.
In contrast, the Exiles are going the other way and have now not won in the league since 3 January.
At that point, London Irish were topping the table but they are now in sixth and outside the top-four play-off places.
Irish were forced into a late change following the withdrawal of Topsy Ojo but they made the perfect start, going ahead in the second minute through Geraghty when Wasps infringed when collecting the kick-off.
But Wasps, who welcomed back flanker Tom Rees after two months out with a knee ligament injury, soon started dominating up front and with Irish scrums disintegrating in the 22, referee Romain Poite lost patience with the Exiles front row and awarded a penalty try.
Declan Danaher was sin-binned for taking out Josh Lewsey off the ball and Wasps increased their lead with a penalty after Geraghty's misplaced pass led to panic in the Irish defence.
Another ruck offence led to another Cipriani penalty, while Geraghty kicked his second before the break to make the score 13-6 to the hosts.
Cipriani's sloppy pass at the start of the second period led to another Geraghty penalty but Wasps took full advantage after Chris Hala'ufia was penalised for a late challenge on Eoin Reddan.
Three forward drives produced a scrum and the home side unleashed a wave of attacks which eventually saw Barnard just burrow his way over in the corner for a try awarded by the video referee.
Cipriani's 62nd-minute penalty made the score 21-9 but Irish gave themselves hope when wing Adam Thompstone showed an electric turn of pace on the wing to outstrip the Wasps defence.
The score led to the visitors piling on the pressure but the Wasps defensive line held firm.
Wasps director of rugby Ian McGeechan:
"We've got to keep winning as many of the outstanding games as we can.
"We're on a decent run at the moment - two defeats since November, but there's some tough games to come.
"There's a lot of head-to-heads in the top eight or nine teams so there's still a lot to play for."
London Irish director of rugby:
"I was very disappointed with some of our basics. You can't question the effort, but rugby's a simple game.
"You want a good platform to play-off, you want quick ball to give yourself scoring opportunities and for large parts of that game we had neither.
"We crafted our way back but made it far more difficult than it should be."
Van Gisbergen; Mitchell, Waldouck, Lewsey, Voyce; Cipriani, Robinson; Payne, Webber, Barnard, Shaw, Skivington, Betsen, Rees, Hart.
Reddan for Robinson (44), Birkett for Barnard (64).
Not Used: Ward, Holford, Leo, Walder, Hoadley.
Geraghty; Thompstone, Seveali'i, Mapusua, Tagicakibau; Catt, Hodgson; Dermody, Buckland, Lea'aetoa, Hudson, Johnson, Danaher, S Armitage, Hala'ufia.
Richards for Hodgson (57), Coetzee for Buckland (54), Skuse for Lea'aetoa (48), Thorpe for Hala'ufia (57), Fisher for Skuse (64).
Not Used: Gower, Homer.
Romain Poite (France)