London Irish's stuttering challenge for the Guinness Premiership title suffered another blow as Heineken Cup quarter-finalists Harlequins achieved their first win at the Madejski Stadium for six years.

Toby Booth's men, playing with 14 men for almost an hour after hooker David Paice was sent off, displayed impressive spirit to hold their London rivals to within seven and achieve a potentially vital losing bonus point.

Paice was sent off in the 22nd minute after an exchange of punches on the Irish 22, and a show of dissent persuaded referee Tim Wigglesworth to show the hooker a straight red card.

Ceri Jones scored the only try of the afternoon to rub salt further into Paice's wounds.

The visiting team's Kiwi playmaker Nick Evans had missed a straightforward-looking penalty opportunity in the seventh minute, after an aggressive start by the visitors.

Irish's first concerted attack produced fluent running from full-back Peter Hewat and wing Adam Thompstone to put Quins under pressure.

Hewat calmly slotted a penalty to gain some reward in the 11th minute, then Evans made up for his earlier miss to level the scores after 17 minutes from in front of the posts after an Irish offence at a scrum.

More inspirational galloping from Hewat led to the returning Topsy Ojo having a first sprint up the wing, but his attempt to out-pace fellow England tourist Mike Brown foundered when his kick ahead went straight into touch.

With Paice off the field, Evans further punished Irish with the ensuing penalty, to howls of derision from the Exiles' fans.

But the home side showed guts to mount an immediate counter-thrust which produced a penalty for Hewat in the 27th minute.

Soon after the half-hour, impressive Quins centre Jordan Turner-Hall almost barged his way under the posts, and the fortunes of Irish went from bad to worse when points machine Hewat was forced to leave the field with a leg injury, following an accidental collision with Ojo.

The half finished with the 14 men controlling proceedings, England reject Steffon Armitage making his presence felt with a rampaging run.

Roared on by their passionate supporters in the 12,000 strong crowd, Irish showed they would not allow numerical disadvantage to make them shut up shop, forcing Quins to be penalised on their 22 just after the restart.

Argentinian scrum-half Alfredo Lalanne took over the kicking duties and nudged the men in green into the lead.

There was a derby fervour at the Madejski, as these traditional London rivals went toe-to-toe. Irish somehow held out for a five-minute spell with Quins camped on their line but eventually Jones was mauled over the whitewash on 49 minutes for the first try of the afternoon.

Evans, however, missed another kick he would normally convert.

South African Gary Botha was relishing the extra space available and a crafty dummy and sprint down the blindside led to Quins mounting another assault on the Irish line.

The Exiles were hanging on, with player/coach Mike Catt having an off-day with his kicking game, unable to relieve the pressure, and with their under-powered scrum creaking.

A desperate attempt to run from the shadow of their posts fell victim to Wigglesworth's whistle at a ruck and Evans knocked over a penalty to seal victory three minutes from the end, despite a frantic last-gasp Irish attack.