Wasps responded to a fierce warning from coach Shaun Edwards to secure a vital Guinness Premiership victory over London rivals Harlequins.

Edwards had told his under-performing players that the next month will make or break their season and they hit Harlequins with a ferocious performance at Adams Park.

Wasps will need to stage one of their now traditional late-season rallies if they are to stand any chance of successfully defending their Premiership title or challenging for the Heineken Cup.

With an away trip to Bath and then European fixtures against Castres and Leinster to come later this month, Wasps will hope this win proves to be a watershed moment.

The victory, which moves them two places up the table, was built on a dominant first-half performance as Wasps opened a 21-3 lead with a try from winger Chris Bishay and a penalty try earned by their powerful pack.

Quins have built a reputation this season for staging dramatic late comebacks and they scored two second-half tries to rally from 21-3 down but in the end had to settle for a losing bonus point.

A quirk in England's elite player agreement may have allowed Harlequins to field both Nick Easter and Ugo Monye when Wasps, much to the frustration of Edwards, had to rest nine of their red rose stars over the last fortnight.

But neither of the Quins duo lasted until the interval as Wasps, desperate to kickstart their stuttering season, completed a comprehensive first-half demolition job on their London rivals.

Wasps hit Quins with aggressive defence - led by James Haskell, man of the match Serge Betsen and Dominic Waldouck - as they made 72 tackles before the interval and missed just two, while Phil Vickery orchestrated the destruction of the Harlequins scrum.

Wasps raced into a 16-0 lead after 25 minutes with three Danny Cipriani penalties and a well-crafted try from academy winger Bishay, who held off two tacklers to score in the corner.

The move had been ignited by Waldouck's scything run through the middle before brilliant quick hands from Cipriani teed up Bishay to stretch over in the corner.

Nick Evans responded with a penalty for Harlequins but it was the briefest of respites for the visitors.

Aston Croall, a late replacement at loose-head for Ceri Jones, had been warned for wheeling the scrum on at least two occasions inside the first half hour before referee Sean Davey finally lost patience and awarded Wasps a penalty try.

The conversion opened Wasps a 21-3 lead. To add insult to injury, four minutes later Croall was sin-binned for killing the ball right under referee Davey's nose after Quins had been warned for repeated infringements at the breakdown.

Wasps did not take advantage of the extra man as Cipriani missed two penalties and, despite his side's dominance, the England fly-half did not enjoy a comfortable afternoon.

In front of England team manager Martin Johnson, Cipriani had two kicks charged down inside his own 22.

He successfully recovered the first to clear his own lines but the second, blocked by Evans as Quins sought a second-half lifeline, led directly to a try.

Wasps full-back Mark van Gisbergen touched down to concede the five-metre scrum and Croall enjoyed a moment of redemption as the Quins scrum earned a penalty try of their own.

Wasps then found themselves down to 14 men when Simon Shaw was sin-binned for tripping Care as the Quins scrum-half attempted to take a quick tap.

Unlike Wasps, Quins did manage to take maximum advantage of the extra man as Care scored a brilliant 45-metre solo try, breaking from the back of a Quins lineout and chipping Van Gisbergen to score near the posts. Evans missed the simple conversion.

Dave Walder - man of the match in four of Wasps' last six games - was given the job of steadying the ship and closing out the win in the last 15 minutes.

Wasps lost replacement flanker Tom Rees to injury in the closing stages but it did not affect their momentum and a penalty from Walder pushed them nine points clear to seal the win.

Quins secured a losing bonus point with an injury time penalty from Chris Malone