Fly-half Riki Flutey landed a dramatic last-minute penalty as London Irish condemned Harlequins to an agonising defeat on their return to the Guinness Premiership.

But it was not only Exiles director of rugby Brian Smith breathing a sigh of relief as Flutey's 45-metre penalty flew through the posts.

Only seven minutes earlier Harlequins appeared to have snatched victory with a try from Welsh prop Ceri Jones, who touched down after a powerful lineout drive.

Referee David Rose awarded the try - only for replays on Twickenham's temporary big screen to show that Harlequins lock Simon Miall had dropped the ball over the line.

In the end, though, justice was done. Harlequins claimed a deserved bonus point for putting up a dogged fight to push London Irish to the limit.

Harlequins fly-half Adrian Jarvis, a late inclusion ahead of former New Zealand international Andrew Mehrtens, scored 14 points from four penalties and a conversion as Quins led for much of the game.

But London Irish, with a strong wind at their backs in the second half, pulled through with Flutey contributing 15 points on top of a first-half try from Topsy Ojo.

Harlequins spent all of last season mixing it with the semi-professional sides of National League One after their relegation from the Premiership in 2005.

They won the division at a canter and then recruited heavily during the off-season - but the newcomers made little impact as Harlequins struggled to create any real openings.

Jarvis, who competed hard with Mehrtens for the starting fly-half duties last season, booted Quins into a 6-0 lead with two penalties in the first 10 minutes.

But otherwise it was London Irish, attempting to reprise the fast, attacking game that brought them such success last season, who looked the more dangerous in the opening exchanges.

Their forwards, marshalled by spiky scrum-half Paul Hodgson, punched deep into Harlequins territory but with Delon Armitage prowling out wide Irish could not quite produce the telling final pass.

It was a recurring problem as they played into a heavy head-wind in the opening half. Flutey escaped superbly through a gap in the Quins defensive line but with Armitage racing up the left touchline Mike Catt's pass flew just out of reach into touch.

Quins' new centre pairing of England international Stuart Abbott and Wales Test star Hal Kuscombe combined well only once to threaten London Irish, but Armitage covered well to bundle full-back Mike Brown into touch right in the corner.

In a moment of madness Abbott was sin-binned for a late dump-tackle on Hodgson and after Flutey had landed the penalty Irish eventually took advantage of their extra man.

Brown, a late replacement for Tom Williams, spilled the ball on his own line. Armitage cleaned up and Ojo squirmed through a forest of bodies to dive over in the corner.

Quins regained the lead six minutes before the interval with Jarvis' third penalty of the half after London Irish number eight Juan Leguizamon was sent to the sin-bin for punching.

Jarvis briefly extended Harlequins' lead with a simple penalty from in front of the posts soon after the interval before London Irish pulled clear.

Flutey landed two penalties as the home side cranked up the pressure and then slotted a cheeky drop goal after the Exiles pack had rumbled 30 yards to within touching distance of the Harlequins line.

The real drama, though, was still to come.

Quins should have had the game won after Jones was awarded the try, but they allowed Flutey two opportunities to win the game in the closing minutes.

Flutey missed the first but sent the second through the posts to earn London Irish an opening day victory.