Relegation-threatened Leeds pulled off one of the shocks of the season by recording a emphatic 23-13 victory over title-chasing London Irish at the Madejski Stadium on Sunday.
From the moment Leeds got their noses in front, the Exiles struggled to find their usual fluency, and despite a succession of penalty-scrums failed to overcome a tremendous defence.
Irish took a grip from the start, forcing Leeds to make a succession of big tackles, but referee Wayne Barnes took exception to one of them and Chris Malone chalked up the game's first points with a fifth-minute penalty.
Leeds reached the Irish 22 from the restart only to be battered back by the pugnacious tackling and running of Steffon Armitage, a force of nature for Irish in recent games.
Irish scorned the chance of doubling their lead in the 11th minute when Tom Homer failed with a penalty from near halfway, and Leeds took immediate advantage, charging upfield and catching Irish offside on the edge of their 22. Ceiron Thomas equalised with the penalty on 13 minutes.
But Leeds quickly fell behind again. Malone kicked a penalty for touch, Eric Lund was penalised for barging in the lineout and Malone's penalty from the right sailed between the posts on 15 minutes.
Irish, however, were not having things all their own way against a team fighting for their lives, and Leeds were level again after 21 minutes when Thomas was on target with his second penalty.
Leeds wasted a great chance to score the game's first try minutes later when Henry Fa'afili hacked clear of a ruck on the right and broke towards the Irish line. But the wing lacked the gas to beat the cover defence, hurled the ball behind him and the attack was snuffed out two passes later.
Leeds were under pressure close to their line on the half-hour, but when Irish thought they had earned a chance of a drive, referee Barnes spotted an offence at the breakdown and Leeds hoofed the ball to safety.
When Irish failed to capitalise on their own lineout, Leeds worked themselves back towards the home 22 and promptly earned another penalty for offside, slammed over by Thomas.
Irish then imploded on 34 minutes. Delon Armitage dropped a probing high ball and his team-mates appeared to freeze for a few seconds, during which Leeds centre Luther Burrell reacted fastest, snaffling up the ball, stepping Peter Hewat and banging the ball down by the post before being tackled.
Thomas completed the score with a simple conversion that almost silenced the home crowd.
Hewat lifted home spirits on 38 minutes when he took a pass from Jamie Gibson and crossed the Leeds line.
Malone's conversion made sure Irish did not change ends seriously adrift.
Leeds took the initiative during the early second-half exchanges, and but for some poor final calls would have increased their lead.
The most glaring was a wasted drop-goal attempt by Thomas that conceded possession to Irish after a prolonged series of Leeds attacking phases that threatened to unhinge the home defence.
Irish gradually regained the upper hand, but despite winning four penalties in the Leeds 22, and requesting scrums for every one, they could not crack the visitors' defence.
The cost was immense as Lee Blackett intercepted a loose pass on 70 minutes and sent Jon Goodridge in for a try, converted by Thomas.
For London Irish:
Pens: Malone 2
For Leeds Carnegie:
Tries: Burrell, Goodridge
Cons: Thomas 2
Pens: Thomas 3
London Irish:15 Peter Hewat, 14 John Rudd, 13 Elvis Seveali'i, 12 Seilala Mapusua, 11 Delon Armitage, 10 Chris Malone, 9 Paul Hodgson, 8 George Stowers, 7 Steffon Armitage, 6 Jamie Gibson, 5 Bob Casey (c),4 Kieran Roche, 3 Faan Rautenbach, 2 Danie Coetzee, 1 Alex Corbisiero.
Replacements:16 David Paice, 17 Dan Murphy, 18 James Tideswell, 19 Matt Garvey, 20 Richard Thorpe, 21 Tom Homer, 22 Jamie Lennard, 23 Ben Stevenson
Leeds:15 Jon Goodridge 14 Henry Fa'afili 13 Luther Burrell 12 Seru Rabeni 11 Lee Blackett 10 Ceiron Thomas 9 Scott Mathie 8 Alfie To'oala 7 Hendre Fourie 6 Calum Clark 5 Marco Wentzel 4 Erik Lund 3 Juan Gomez 2 Andy Titterrell 1 Mike MacDonald.
Replacements:16 Phil Nilsen 17 Gareth Hardy 18 Phil Swainston 19 Tom Denton 20 Rhys Oakley 21 Andy Gomarsall 22 Joe Ford 23 Henry Paul
Referee: Wayne Barnes