Harlequins snatched an unlikely win by scoring three opportunist tries at Sixways to leave Worcester in desperate trouble at the bottom of the Guinness Premiership table.
Full-back Mike Brown and wingers Dave Strettle and Simon Keogh punished some glaring defensive errors from the Warriors, with recalled fly-half Andrew Mehrtens adding three conversions and two penalties.
Worcester appeared to have taken control of the game until injuries to two Harlequins props forced uncontested scrums for the final half-hour of the game.
James Brown had kept the scoreboard ticking over with five penalties but it took 70 minutes for them to find a way through the visitors’ defence when replacement flanker Gavin Quinnell smashed his way over from a line-out.
The result leaves Worcester nine points adrift of Northampton at the bottom of the table and their only consolation is that their next game is against the Saints at Franklin’s Gardens on New Year’s Day.
For this key game Worcester had recalled Marcel Garvey on the wing and added some extra bulk to their pack with Tevita Taumoepeau and Aleki Lutui coming into the front row.
Harlequins made a significant switch at fly-half where former All Black Mehrtens replaced Adrian Jarvis to start his first Premiership game since September 9.
Paul Volley returned to lead the side from the back-row with Mel Deane in for Hal Luscombe at centre and Keogh, Nick Easter and James Evans were also recalled as boss Dean Richards made major changes in the wake of the 20-16 defeat against Saracens.
Both sides betrayed their nerves early on, Worcester making a mess of the kick-off and conceding a first-minute penalty which Mehrtens stroked over from wide on the right with his opposite number Brown levelling in the fifth minute after the Quins scrum disintegrated.
Worcester dominated most of the first half though, with Thomas Lombard just failing to ground Brown’s chip through the Quins defence and the fly-half nudged his side in front with his second penalty after 12 minutes.
But they conceded the softest of tries against the run of play a minute later when the ball squirted away from Thinus Delport and full-back Mike Brown hacked on and touched down with Mehrtens converting.
And some more slack defending allowed Strettle to wriggle out of a tackle and stretch over for a second try, and a second Mehrtens conversion opened up a 17-6 lead after 21 minutes.
Despite their frailties behind the scrum, Worcester were still dominant up front and pounded their way back into scoring positions for Brown to chip away at the lead with penalties after 27 and 29 minutes.
They appeared to have seized control when Brown kicked a fifth penalty five minutes into the second half after Quins lock Ollie Kohn was sin-binned for sneaking into the wrong side of a driving maul.
But the advantage evaporated when Quins lost a second prop to injury – Mike Ross following Ceri Jones into the changing room – forcing uncontested scrums for the rest of the game.
Quins then struck with a third opportunist try when playing with 14 men after Delport spilled the ball and Keogh regathered and sprinted 60 metres to score.
Mehrtens added a third conversion and his 62nd minute penalty established a 12-point lead that forced Worcester to open up the game in unfamiliar fashion.
They worked their way into Harlequins territory before unleashing a more familiar weapon – a short-range line-out that ended with 20 stone replacement Quinnell battering his way over on the right.
The try earned them a valuable bonus point but Brown could not convert and Worcester were kept at arm’s length as Mehrtens used all his know-how to run down the clock.