While Quins march on towards potentially pivotal Pool Six home and away encounters against four-time European champions Toulouse next month, Gloucester face making an early exit following two defeats in a row.
First-half tries by full-back Mike Brown and centre Matt Hopper put Quins in charge, but once again it was goalkicker Nick Evans who underpinned victory as he booted three penalties and two conversions.
Quins' England number eight Nick Easter completed an emphatic away success when he touched down eight minutes from time, inflicting a heaviest Heineken home defeat on Gloucester since Stade Francais demolished them 27-0 at Kingsholm six years ago.
Gloucester created their fair share of opportunities in attack - Mike Tindall delivered another strong display following his £25,000 Rugby Football Union fine and being axed from the national squad - yet only had three Freddie Burns penalties to show for it.
And they are now left on the edge of pool stage elimination for a fifth time in their last six European campaigns.
But Quins, with Aviva Premiership bottom club Newcastle their next opponents at the Twickenham Stoop tomorrow week, have gone almost seven months since they last lost.
The latest victory owed much to outstanding defensive organisation and hard-working shifts at the coalface from players like prop Joe Marler and skipper Chris Robshaw.
And their bubble does not look like bursting any time soon under the impressive guidance of rugby director Conor O'Shea, who has moulded a team high on quality and work-rate.
Gloucester showed two changes from the side beaten narrowly by Toulouse last weekend. Wing Lesley Vainikolo and hooker Scott Lawson gained starts, while Quins made three switches following a hard-fought victory over Connacht.
Joe Gray featured at hooker, with former Cornish Pirates player Hopper taking over from ankle injury victim George Lowe and lock Tomas Vallejos replacing Olly Kohn.
Quins took just six minutes to breach Gloucester's defence, striking from their first attack when centre Jordan Turner-Hall found Brown with a scoring pass and he cut an exquisite angle for a neatly-crafted try.
Evans converted, but Gloucester stormed back through a trademark Vainikolo charge that resulted in him being bundled into touch just inches from the corner flag.
A Burns penalty opened Gloucester's account, yet that was quickly cancelled out by an Evans strike when home lock Will James infringed and Quins were good value for a 10-3 lead after an opening quarter they dominated.
Another Burns penalty cut the deficit to four points, but the game's early promise evaporated despite Vainikolo and flanker Akapusi Qera testing Quins' defence through some strong midfield thrusts.
Just when Gloucester looked as though they would go into half-time only four points adrift, though, Quins stung them with a try in the closing seconds.
Hopper was the beneficiary of impressive approach work this time, gathering scrum-half Karl Dickson's pass and sliding to the line for a try that French referee Christophe Berdos awarded after consulting the television match official.
Evans' conversion attempt hit the left-hand post, yet Quins were good value for a 15-6 interval advantage that left Gloucester with it all to do.
Another Evans penalty extended the lead barely a minute after the restart, only for Quins to offer their opponents a lifeline by temporarily being reduced to 14 men.
Flanker Maurie Fa'asavalu was yellow-carded by Berdos for a dangerous tackle on Qera, and Burns booted the resulting penalty before Gloucester's forwards looked to up the ante.
Gloucester put together their most threatening spell of sustained pressure, and it should have resulted in a try, but centre Henry Trinder spilled possession diving over the line as Marler executed a stunning tackle.
It was to prove their final clear-cut chance, and Quins sealed the deal when Easter galloped clear in open play to touch down and round off another thoroughly satisfying afternoon's work from the confident Londoners.
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