Academy products Tom Guest, standing in for England's World Cup Number 8 Nick Easter, and 19-year-old centre Jordan Turner-Hall scored the early second-half tries which put the game beyond the reach of the Yorkshire side.

They had taken the lead with a first-half penalty drive as Leeds illegally halted a Quins' maul near their own line.

Chris Malone, a close-season fly-half signing from Bath, contributed 18 points with two penalties, four conversions, and the fourth Harlequins try which ensured the bonus point.

Simon Keogh, Harlequin's fourth choice scrum-half behind England's World Cup number nine Andy Gomarsall, Samoa's Steve So'oialo and the injured Danny Care, raced in for the fifth Harlequins try.

Leeds replied with a penalty from full-back Leigh Hinton and Rhys Oakley and replacement Vili Ma'asi, with Richard Welding landing one conversion.

Following a drab first half, in which Leeds enjoyed plenty of possession but failed to breach a well-drilled Quins defence, Guest sparked an entertaining second-half when he grabbed the ball from the base of a scrum in the 42nd minute and left Leeds full-back Hinton beaten for pace with a curving 35-metre run round the outside to dive over for his five-second try.

Six minutes later Turner-Hall raced in after the Harlequins' forward had spent a lengthy spell camped on the Leeds line.

Nothing much went right for the visitors from the fourth minute when lock John Dunbar limped off with a leg injury.

It took them 38 minutes to open their account with a penalty from Hinton and, although they battled gamely, they failed to make too much impression.

Harlequins' Guest was sent to the sin-bin 11 minutes from time for falling down a ruck but his absence came too late to affect the outcome.

Leeds, on the evidence of this performance, face an uphill struggle to defy the bookmakers who have installed them as favourites to be relegated back to National Division One.

They have now conceded 88 points in their opening two defeats, following the 49-24 setback at Gloucester last weekend.