In wet conditions, Irish were looking for revenge after the last encounter between the two sides, where Quins came out on top. They started the better team, with the ball spending the majority of the time in the Quins half.
After 14 minutes gone on the clock, London Irish were rewarded with a penalty after Quins' lock James Percival, making his first start of the season, was penalised with a yellow card for pulling down a maul. Luckily for Quins, fly half's Jeremy Staunton's kick failed to fall between the posts.
Just four minutes later, London Irish thought they had opened up the score board when number 8 Phil Murphy touched down the ball in the left hand corner, but the referee saw an obstruction and the the try was disallowed.
An large overlap saw Irish rewarded for all the pressure, with number 8 Phil Murphy taking full advantage and put the first 5 points on the Quins' board. Jeremy Staunton, who was a late replacement for the starting line up after Geragherty damaged his wrist in training, missed the conversion.
Quins hit back after 32 minutes with a break from open side flanker Will Skinner, resultng in a well worked scrum on the Irish's five metre line. Quins capitalised on their position with Chris Hala'ufia picking up the ball from the back of the scrum diving over to score a try in the right hand corner. It was quickly converted by Adrian Jarvis and Quins took a suprising lead (5-7).
After 38 minutes, Delon Armitage slotted home a penalty to put London Irish back in front, but this was cancelled out by a penalty from Adrian Jarvis in the closing seconds of the first half. Sending Quins into the break leading 10-8.
The second half saw no more points for either side, although this wasn't due to a lack of chances.
A missed, long range penalty from Jarvis just after the start of the second half was followed by a sigh of relief from Quins supporters when a second Irish try was disallowed, this time coming from Peter Richards, just back from England's world Cup squad.
Both teams saw a number of replacements, with Quins changing Tom Guest for captain Paul Volley, Chris Malone for Adrian Jarvis and Tani Fuga for Chris Brooker.
Malone was unlucky to see his only attempt on goal hit the right post, but with the final whistle following, Quins walked away with their first EDF Energy Cup win.
During week commencing 22nd April Harlequins will launch an innovative, new Membership Scheme which will replace the existing Season Ticket Holder Programme. Further details of the scheme will be announced in due course.