Reigning Aviva Premiership champions Harlequins slipped to their third successive league defeat as Gloucester won a scintillating contest 17-15 at Kingsholm.
With both teams readily running possession - and a referee in J P Doyle who allowed the game to flow - it produced an encounter of the highest quality that went Gloucester's way when flanker Akapusi Qera touched down 10 minutes from time.
Quins led 12-3 at half-time following tries from hooker Rob Buchanan and wing Sam Smith, but play-off contenders Gloucester refused to lie down and wing Jonny May's 43rd-minute score kept them in contention.
Quins will drop to fourth spot, one place above Gloucester, if Northampton beat Leicester tomorrow, as for the first time in rugby director Conor O'Shea's three-year reign they slipped to a third league loss on the bounce.
Fly-half Nick Evans chipped in with a penalty and conversion for Quins, while his opposite number Freddie Burns converted both Gloucester tries and kicked a penalty as his team held their nerve to prevail.
It was fast, furious and occasionally frantic, and a crowd of just under 15,000 revelled in the attacking intensity that both sides brought to the party. Counter-attacking was the order of the day, rather than a safety-first kicking approach, which resulted in a game to savour. Quins rested their captain and England skipper Chris Robshaw, with Luke Wallace replacing him in the back-row and Joe Trayfoot taking over from an ill blindside flanker Tom Guest in a side led by number eight Nick Easter.
Gloucester handed Henry Trinder a start in midfield, where he replaced Mike Tindall, and there was a first Premiership start for 21-year-old hooker Koree Britton, but the home side suffered a blow when captain Jim Hamilton limped off after just five minutes - Will James took over from him - and Quins looked to capitalise through centre George Lowe's powerful run that gave his team an attacking platform. When Trinder missed a tackle on Buchanan just three minutes later, the Quins hooker powered over wide out despite home scrum-half Dan Robson's despairing lunge.
Evans' touchline conversion attempt hit the post, yet Quins had made a powerful statement against opponents who looked to be carrying a hangover from last weekend's dour home victory over relegation favourites London Welsh.
The home pack, inspired by Qera and his fellow flanker Tom Savage, injected some urgency, though, only for a poor kick by England centre Billy Twelvetrees to undo their good work.
A Burns penalty cut the deficit after 20 minutes, yet Quins' response proved a wonderfully-assured one as a superb Evans chip over Gloucester's defence was caught by Smith, who sprinted clear for the touchdown. Evans added the conversion, leaving Gloucester in a degree of trouble at 12-3 adrift, and it could have been even worse had scrum-half Danny Care's pass to Lowe not been ruled forward by referee JP Doyle.
Quins were far more clinical than their hosts, yet it did not deter Gloucester from launching a thrilling long-range attack highlighted by a brilliant Trinder pass from behind his back that should have led to a try for full-back Rob Cook, but he knocked on.
Burns then missed a penalty chance just before half-time, meaning that Quins retained control of the scoreboard following a pulsating 40 minutes high on skill and endeavour. Gloucester knew they had to strike first after the break, and they duly delivered inside three minutes through a spectacular score by May.
When a Quins attack broke down deep inside Gloucester territory, their first instinct was to run it back, with Charlie Sharples skating around his opposite number Smith before quickly recycled possession resulted in May crossing on the other wing.
Burns landed the conversion, making it 12-10, and although Evans booted a penalty for Quins, Gloucester exerted considerable scrum pressure that ultimately resulted in Qera powering over after Quins' replacement hooker Joe Gray had been sin-binned.
Burns again converted, and there was no way back for Quins as their hopes of a home play-off tie continue to fade just nine days before they host Heineken Cup quarter-final opponents Munster.
Gloucester No.8 Sione Kalamafoni was named man of the match and he admitted that the full house at Kingsholm helped them overcome one of the most difficult challenges they are likely to face this season.
"The atmosphere was unbelievable and it was a physical game, so fantastic for the boys," he said. "We dug in and got the win. It's always difficult against a team like that. "There is lots we can improve defensive wise. We gave away two tries and there are things we need to work on it in the week, but we are always confident we can win here at Kingsholm."
Harlequins' director of rugby Conor O'Shea refused to be too critical of his team following a short turnaround after their loss to Saracens. He remains confident that they will be in the play-offs come the end of the season, so long as they match the performance against the cherry and white.
"If we play like that for the rest of the season, we will be very happy because I think we will be right where we need to be," he said. ""The feeling at the moment is pretty hard to take, but I thought our boys were absolutely outstanding five days after our previous game (against Saracens).
"If we play like that, I don't think there are many teams who will want to play against us. I am proud of the lads."