Ryan Lamb punished his former club with an immaculate goal kicking display as London Irish climbed to second place in the Aviva Premiership Rugby table.
The Exiles fly-half booted 13 points through a five-from-five return, condemning Gloucester to their second defeat in three starts this term. Hooker James Buckland and number eight George Stowers, who was sent off during last weekend's narrow loss at Bath, added tries in each half to leave Irish three points behind unbeaten leaders Northampton.
Irish once again look title play-off material, even at this early stage of proceedings, yet Gloucester could find themselves facing a long, hard winter.
Despite parading a dozen internationals in their starting line-up, Gloucester lacked tactical nous behind the scrum and were too often bullied by an Irish pack that will inevitably experience far more punishing tests this season. The only real surprise was that Gloucester clinched a losing bonus point courtesy of wing Lesley Vainikolo's injury time effort that substitute Tim Taylor converted to follow three earlier penalties by Nicky Robinson.
Irish were without injured England international flanker Steffon Armitage, so Kieran Roche switched from lock and Nick Kennedy resumed his prolific second-row partnership with Bob Casey, while centre strongman Seilala Mapusua partnered summer signing Dan Bowden in midfield.
Gloucester handed Scotland lock Jim Hamilton a debut following his arrival from Edinburgh as the Madejski Stadium visitors looked to kick-start their campaign after losing against Aviva Premiership Rugby newcomers Exeter and then struggling past Leeds Carnegie by a point at Kingsholm.
Lamb and Robinson exchanged early penalties but Irish looked dangerous from the outset, cleverly mixing their running and kicking games before Gloucester's defence was unlocked after 19 minutes. Precision passing by the Irish backs stretched Gloucester in all directions before flanker Declan Danaher delivered a scoring ball to Buckland and Lamb converted for a 10-3 lead.
Although Robinson cut the deficit through his second penalty, Gloucester continued to concede huge amounts of territory. And they were their own worst enemies at times, illustrated when full-back Charlie Sharples fumbled possession over Gloucester's dead-ball line from a wayward Vainikolo assist, conceding a five-metre scrum.
Irish piled on the pressure through their forwards, but Gloucester almost scored on the stroke of half-time after hooker Scott Lawson took scrum ball against the head. Robinson launched a counter-attack out of Gloucester's 22, and just when Irish looked to have the danger covered Lamb threw out a reckless pass that put his team back into reverse gear and saw them narrowly escape conceding a try.
Irish should have been further ahead as the teams trooped off, yet Gloucester were still in contention even if they offered little evidence of any attacking prowess. Robinson quickly completed his penalty hat-trick in a further wake-up call for the home team, and it took another Lamb strike after Irish's forwards were held over Gloucester's line to restore a four-point advantage.
Irish eagerly attempted to inject some urgency, sparked by scrum-half Paul Hodgson's darting breaks in front of watching England attack coach Brian Smith, and with Gloucester's discipline showing signs of fraying, another Lamb penalty made it 16-9.
Entertainment value for the crowd of just over 8,000 fans was minimal though, and with both sides regularly conceding penalties there was a frustrating stop-start nature to the contest. But knowing one more score would probably make the game safe, Irish stepped up a gear early in the final quarter.
Mapusua stormed into Gloucester territory, and when quick ball was rifled out to the Irish backs wing Johnathan Joseph found an unmarked Stowers, who blasted through Robinson's challenge. Lamb added the extras, and with Irish safe on the scoreboard they began to rediscover the attacking enterprise that has become a trademark under their coaching team of Toby Booth and Mike Catt.
Gloucester, in contrast, lost their shape and composure despite the consolation try as the pressure is now inevitably cranked up on head coach Bryan Redpath prior to next Saturday's appointment with Wasps.