London Irish moved to second place on the Aviva Premiership standings thanks to a 23-16 win over Gloucester at the Madejski Stadium on Sunday.
Fly-half Ryan Lamb produced a flawless kicking display to help sink his former club with tries in each half from hooker James Buckland and number eight George Stowers.
Lamb kicked 13 points as he went five from five with his kicking 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 after they lost their second game out of three so far.
Despite parading a dozen internationals in their starting line-up, Gloucester lacked tactical nous behind the scrum and were too often bullied - but they at least grabbed a losing bonus point through Lesley Vainikolo's injury-time effort that substitute Tim Taylor converted to follow three earlier penalties by Nicky Robinson.
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.
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.
Irish stepped up a gear early in the final quarter though and 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.
For London Irish:
Tries: Buckland, Stowers
Cons: Lamb 2
Pens: Lamb 3
Pens: Robinson 3
London Irish: 15 Delon Armitage, 14 Topsy Ojo, 13 Seilala Mapusua , 12 Daniel Bowden, 11 Jonathon Joseph, 10 Ryan Lamb, 9 Paul Hodgson, 8 George Stowers 7 Declan Danaher , 6 Kieran Roche, 5 Bob Casey, 4 Nick Kennedy, 3 Faan Rautenbach, 2 James Buckland, 1 Clarke Dermody (c).
Replacements: 16 David Paice, 17 Max Lahiff, 18 Alex Corbisiero, 19 Matt Garvey, 20 Jonathon Fisher, 21 Sailosi Tagicakibau, 22 Chris Malone, 23 Darren Allinson
Gloucester:15 Charlie Sharples, 14 James Simpson-Daniel, 13 Mike Tindall (c), 12 Eliota Fuimaono-Sapolu, 11 Lesley Vainikolo, 10 Nicky Robinson, 9 Rory Lawson, 8 Brett Deacon 7 Andy Hazell, 6 Alasdair Strokosch, 5 Alex Brown, 4 Jim Hamilton, 3 Pierre Capdevielle, 2 Scott Lawson, 1 Alasdair Dickinson.
Replacements: 16 Olivier Azam, 17 Nick Wood, 18 Rupert Harden, 19 Dave Attwood, 20 Luke Narraway, 21 Dave Lewis, 22 Tim Taylor, 23 Tim Molenaar
Referee: Tim Wigglesworth