Edinburgh notched up an impressive 29-10 Heineken Cup win over Leinster at Murrayfield on Saturday.
The Dubliners needed a win to keep alive their prospects of squeezing into the knock-out stages - but the fired-up Gunners stunned them for the second season on the trot.
And it was no more than Andy Robinson's born-again troops deserved. They withstood an early barrage and then snuffed out the province through a combination of brave defence and streetwise attacking.
Leinster made the more urgent start and they enjoyed the benefit of a highly debatable refereeing verdict.
A home player was blatantly blocked with the ball nowhere near - yet it was the visitors who were awarded a penalty by Welshman Tim Hayes.
And Argentinian World Cup hero Felipe Contepomi made no mistake from close range.
The Irish side maintained the early momentum and pinned the Gunners back inside their own danger zone.
To add to their worries, the hosts were struggling to win their lineouts and were under heavy pressure in the scrums.
They broke off the shackles in the 12th minute, however, to level the contest via the boot of Phil Godman after Brian O'Driscoll was guilty of a high challenge.
Edinburgh were looking much more comfortable and Leinster were warned for committing a series of set-piece offences.
The resurgence of the capital outfit was again rewarded as Godman doubled his penalty tally.
And Leinster were rocked by a further setback when Test winger Shane Horgan was forced off with rib damage sustained in a challenge by former team-mate Ben Gissing.
The pro-Edinburgh trend continued in the build-up to the interval. And their enterprise earned a third penalty for Godman, leaving the province with plenty to think about.
Even better was to come for the home brigade as they carved out a marvellous try for fit-again international Simon Webster.
The initial damage was inflicted by Andy Turnbull, who lured the markers before timing his feed to Webster with perfection.
Godman gleefully added the extra points to open up a gap of 13 points.
Rattled Leinster hit back positively with Guy Easterby burrowing to the line.
The decision was referred to TV ref Tony Rowlands, and to the delight of the Edinburgh fans he ruled out the score.
Rowlands was again called into action two minutes later in the wake of a Leinster pack surge - and the outcome was identical.
The verdict was the same when he was invited to make a third decision on the trot.
But Edinburgh's run of good fortune vanished in the seventh minute of stoppage time when Hayes handed Leinster a penalty try, insisting O'Driscoll had been obstructed.
The conversion was a formality for Contepomi.
Skipper Mikey Blair eased the Gunners' jitters immediately after the restart when he clipped over an opportunist drop goal from close-range.
Then came another major blow for the Dubliners.
Their gamble in trying to run the ball clear of their own 22-area backfired in devastating fashion as Ben Cairns pounced on Rob Kearney's floated pass before cruising in for an interception touchdown.
Godman's conversion stretched the lead to 16 points and the hosts were firmly in the driver's seat.
Desperate Leinster again stepped up the pace, but still the home markers were giving nothing away.
And any prospect of a dramatic late rally was wrecked as Godman hit penalty number four.
Tries: Webster, Cairns
Cons: Godman 2
Pens: Godman 4
Drop Goal: M.Blair
Edinburgh: 15 Ben Cairns, 14 Andy Turnbull, 13 Nick De Luca, 12 John Houston, 11 Simon Webster, 10 Phil Godman, 9 Mike Blair (c), 8 David Callam, 7 Ross Rennie, 6 Simon Cross, 5 Ben Gissing, 4 Matt Mustchin, 3 Craig Smith, 2 Ross Ford, 1 Augusto Allori.
Replacements: 16 Andrew Kelly, 17 Allan Jacobsen, 18 Craig Hamilton, 19 Allister Hogg, 20 Ben Meyer, 21 David Blair, 22 Calum MacRae.
Leinster: 15 Girvan Dempsey, 14 Shane Horgan, 13 Brian O'Driscoll (c), 12 Gordon D'Arcy, 11 Rob Kearney, 10 Felipe Contepomi, 9 Guy Easterby, 8 Jamie Heaslip, 7 Shane Jennings, 6 Stephen Keogh, 5 Malcolm O'Kelly, 4 Leo Cullen, 3 Stan Wright, 2 Bernard Jackman, 1 Ollie le Roux.
Replacements: 16 Brian Blaney, 17 Cian Healy, 18 Cameron Jowitt, 19 Keith Gleeson, 20 Chris Keane, 21 Jonathan Sexton, 22 Luke Fitzgerald.
Referee: Tim Hayes (Wales)
Touch judges: Nigel Whitehouse (Wales), Richard Hughes (Wales)
Assessor: JoŽl Dumť (France)
Television match official: Tony Rowlands (Wales)