London Irish maintained their push for a Guinness Premiership play-off place with a well-earned 29-14 win over Harlequins on Sunday.
Quins were made to pay for their frequent misdemeanours, with Tom Homer kicking five penalties to ensure victory for Irish.
The hosts were forced into playing outside half Ryan Lamb at scrum-half as they were without their three regulars in that position - Paul Hodgson is on England duty while both Alfredo Lalanne and Peter Richards are injured.
The home side were first on the scoreboard, taking the lead after five minutes with a 30-metre penalty from Homer after Quins lost a lineout on their own 22.
Four minutes later Homer had a chance to extend the lead but his long range effort went narrowly wide.
Quins then built up a period of pressure and were unlucky not to score on two occasions, players being held up over the Irish tryline but unable to ground the ball.
From one of the resulting five-metre scrums, referee Wayne Barnes awarded a penalty try as the Irish scrum broke up.
Nick Evans converted to give the visitors a 7-3 lead after 19 minutes.
Homer then reduced those arrears with another penalty moments later.
Irish regained the lead after 26 minutes when Chris Hala'ufia slipped a tackle in midfield to provide the scoring pass for Steffon Armitage, with the try being converted by Homer.
The visitors were dealt a further blow when their number eight, Tom Guest, had to leave the field wth an injury.
With five minutes to go until the interval, Quins were offside in midfield and Homer's easy penalty extended the Irish advantage to nine points before Quins wing David Strettle left the field with an injury.
To cap a disastrous second quarter for Quins, Homer kicked another penalty to leave the visitors 19-7 adrift at half-time.
Irish had the better of the early exchanges in the second half but it was Quins who had the first opportunity to score but Evans was short with a 50-metre penalty attempt.
Very poor lineout work and ill-discipline prevented Quins from building up any impetus and, when the visitors were once again offside, Homer kicked another goal.
Quins continued to be the authors of their own misfortune and the game was effectively sealed in Irish's favour after 58 minutes when Bob Casey intercepted a stray Quins pass to send fellow lock Nick Kennedy on a 35-metre run to the line, Homer converting with an excellent touchline kick.
Quins continued to battle away and probably had more of the play in terms of possession and territory but had great difficulty in making any real headway against some thunderous tackling from Irish.
In the latter stages, the game degenerated in terms of quality due to the usual plethora of replacements. With four minutes to go, Quins at last got something for their battling effort when George Lowe finished off a neat movement, with Evans adding the conversion.
For London Irish:
Tries: Armitage, Kennedy
Cons: Homer 2
Pens: Homer 5
Tries: Penalty try, Lowe
Cons: Evans 2
London Irish: 15 Tom Homer, 14 Topsy Ojo, 13 Elvis Seveali'i, 12 Seilala Mapusua, 11 Peter Hewat, 10 Ryan Lamb, 9 Alfredo Lalanne, 8 Chris Hala'Ufia, 7 Steffon Armitage, 6 George Stowers, 5 Bob Casey, 4 Nick Kennedy, 3 Faan Rautenbach, 2 David Paice, 1 Dan Murphy.
Replacements: 16 James Buckland, 17 Max Lahiff, 18 James Tideswell, 19 Kieran Roche, 20 Jamie Gibson, 21 Chris Malone, 22 Peter Richards, 23 Mike Catt.
Harlequins: 15 Mike Brown, 14 David Strettle, 13 George Lowe, 12 Jordan Turner-Hall, 11 Sam Smith, 10 Nick Evans, 9 Karl Dickson, 8 Tom Guest, 7 Will Skinner (c), 6 Chris Robshaw, 5 Lewis Stevenson, 4 James Percival, 3 John Andress, 2 Matt Cairns, 1 Ceri Jones.
Replacements: 16 Tani Fuga, 17 Aston Croall, 18 James Johnston, 19 Tomas Vallejos, 20 Chris York, 21 Steve So'oialo, 22 Rory Clegg, 23 Nils Mordt.
Referee: Wayne Barnes