Leeds were left staring into the Premiership abyss after suffering an emphatic 46-11 loss to Harlequins at the Stoop on Saturday.
Full-back Mike Brown scored twice for Quins, who are unbeaten at home since September, while wingers Tom Williams and David Strettle, centre George Lowe and replacement hooker Chris Brooker also touched down.
Former All Black Nick Evans added 14 points, with two penalties and four conversions, with his replacement Rory Clegg converting the final try.
Leeds replied with two penalties from fly-half Ceiron Thomas and a last-minute consolation try from number eight Alfie To'oala.
The Yorkshire side failed to capitalise on the numerous inroads their powerful Fijian centre Seru Rabeni made into the home defence as they suffered their third successive defeat following the mini-revival which took them off the bottom of the table.
Evans kicked Quins ahead in the seventh minute with a 40-metre penalty after Leeds were brought back for a late challenge on home full-back Mike Brown after he fielded a kick.
Six minutes later the opportunist thinking of Evans created the first try.
Taking a quick lineout, the Kiwi fly-half found full-back Mike Brown who scythed through the middle, drawing the defence before throwing a long pass which sent winger Williams in unchallenged at the corner.
Rabeni was proving a real handful, crashing through three tackles in one Leeds attack and beating two men in the next.
But Harlequins hit back and the pace of Williams took him past three Leeds defenders before the Yorkshire side conceded a penalty in the 25th minute, landed by Evans to put Quins 13-0 ahead.
Leeds opened their account with a penalty from Thomas three minutes later after a Quins scrum infringement.
England number eight Nick Easter, making a welcome return for Harlequins, provided stability at the base of the scrum and foraging well at the breakdown.
Leeds tried to get back into the game but Leigh Hinton lacked support after a piercing run and Harlequins hit them on the break to score again after 52 minutes.
It started with Easter swooping to pick up a loose ball following a ruck to find Evans and ended with Brown picking up and forcing his way over after Strettle was stopped just short of the line by Hinton.
Thomas landed his second penalty for Leeds in the 60th minute but their hopes of salvaging anything from the match were ended a minute later when lock Calum Clark, bound for Northampton at the end of the season, was yellow-carded for a wickedly late challenge on Evans after he had kicked clear.
Harlequins immediately cashed in on their numerical superiority with four tries in the space of nine minutes.
Evans and Strettle combined to send young centre George Lowe in after 63 minutes and three minutes later the depleted Leeds pack proved no match for a huge 25-metre forward drive which took Brooker over for the bonus-point try.
Leeds struck again with Brown's second try in the 69th minute. Williams had his shirt tugged by Hinton as he chased his own kick but Brown won the chase to get a hand on the loose ball.
Three minutes later Strettle showed his pace, outstripping the Leeds defence on a run from halfway, for their sixth try, and To'oala's reply a minute from time proved inconsequential.
Tries: Williams, Brown 2, Lowe, Brooker, Strettle
Cons: Evans 4, Clegg
Pens: Evans 2
For Leeds Carnegie:
Pens: Thomas 2
Harlequins: 15 Mike Brown, 14 David Strettle, 13 George Lowe, 12 Jordan Turner-Hall, 11 Tom Williams, 10 Nick Evans, 9 Danny Care, 8 Nick Easter, 7 Will Skinner (c), 6 Tom Guest, 5 George Robson, 4 James Percival, 3 John Andress, 2 Tani Fuga, 1 Ceri Jones.
Replacements: 16 Chris Brooker, 17 Aston Croall, 18 James Johnston, 19 Lewis Stevenson, 20 Chris York, 21 Karl Dickson, 22 Rory Clegg, 23 Nils Mordt.
Leeds Carnegie: 15 Leigh Hinton, 14 Henry Fa'afili, 13 Seru Rabeni, 12 Scott Barrow, 11 Lee Blackett, 10 Ceiron Thomas, 9 Scott Mathie, 8 Alfie To'oala, 7 Hendre Fourie, 6 Calum Clark, 5 Marco Wentzel (c), 4 Erik Lund, 3 Juan Gomez, 2 Andy Titterrell, 1 Mike MacDonald.
Replacements: 16 Phil Nilsen, 17 Gareth Hardy, 18 Phil Swainston, 19 Kearnan Myall, 20 Rhys Oakley, 21 Andy Gomarsall, 22 Joe Ford, 23 Richard Welding.
Assistant referees: Roger Baileff, Andrew Pearce
TMO: Roy Maybank