Substitute Simon Webster sealed a stunning triumph as the Gunners came from behind to clinch one of the biggest wins in their history in their Heineken Cup Pool Six clash with former champions Wasps at rain-lashed Murrayfield.

Paul Sackey's late try for Wasps looked to have dashed home hopes but Webster then pounced on a handling error by Sackey to race over in the first minute of injury time.

Skipper Chris Paterson fluffed his conversion from under the posts but Edinburgh held out for seven tense minutes of stoppage time to create a massive upset against Lawrence Dallaglio's Premiership giants.

Wasps took control early on when full-back Mark van Gisbergen was spot on with two easier shots at goal at the other end.

But Edinburgh were in no mood to lie down to the favourites and they produced the first signs of resistance when a slick handling move took them deep into enemy territory before Marcus Di Rollo was comprehensively flattened.

The deficit was reduced when Paterson slotted a confident penalty.

But straight from the restart the Murrayfield men were caught napping when van Gisbergen embarked on a mazy 60- metre run which led to the game's first try.

The full-back jinked, dummied and side-stepped his way through several tackles before Mike Blair eventually halted his run five metres short.

However, Jonny O'Connor was first to react and the flanker drove over to give van Gisbergen an easy conversion under the posts.

Van Gisbergen turned from hero to villain from the kick-off when he was caught by the Gunners pack who drove him over his own line.

The streetwise Wasps pack then collapsed the resulting scrum and Edinburgh had to be content with Paterson's second penalty.

But they got their reward when Paterson notched a superb opportunist try in 28 minutes.

The home side nicked possession on halfway and when the ball was booted ahead winger Paterson outpaced Josh Lewsey in a 40-metre sprint for the touchdown.

Paterson converted his own try from the right touchline but the Gunners were level for just two minutes before Wasps restored their lead with a huge slice of luck.

Van Gisbergen appeared to have squandered the chance when his penalty rebounded from an upright but quick-thinking Lewsey was first to react and the England centre was unchallenged as he plunged over.

Van Gisbergen made no mistake with the conversion.

Paterson squandered a further two penalty chances on either side of the break but the battling Scots continued to surge forward as Wasps wobbled.

Edinburgh set up a thrilling finale when they notched the best try of the game.

Francisco Leonelli linked with Phil Godman whose superb reverse pass released Hugo Southwell.

The full-back was half-tackled by Sackey but his momentum took him over in the corner.

Only another missed kick by Paterson denied the Gunners a share of the lead but the skipper atoned with a couple of penalties which took his side four points ahead.

Van Gisbergen reduced the deficit to a single point after Simon Taylor was penalised for obstruction at a lineout.

But the Scottish side looked the more likely to score again and they almost notched a crucial third try when Godman's crafty kick ahead had Wasps back-pedalling again.

And only a kind bounce allowed van Gisbergen to deny Southwell his second touchdown.

Paterson's fifth penalty restored the four-point gap before the Gunners were stung by a Wasps counter-attack.

The Premiership big guns switched the ball from left to right where Tom Voyce fed Sackey to score in the corner.

It looked all over when van Gisbergen landed another penalty but Webster's stunning score sealed a famous win.