Substitute Lesley Vainikolo scored with 90 seconds left to give Gloucester their fourth successive Aviva Premiership Rugby win after an enthralling Kingsholm tussle.
The former England wing powered over in blockbusting fashion, claiming a try that required confirmation from the video referee before it was awarded.
Goalkickers Nicky Robinson and Billy Twelvetrees had earlier cancelled each other out at Kingsholm, slotting four penalties apiece.
Robinson's 72nd-minute miss after Tigers centre Matt Smith was sin-binned looked to have cost his team dear, but Vainikolo got him out of jail. Robinson converted Vainikolo's score for a 14-point haul, leaving champions Leicester still searching for a first domestic away-day success this season.
Gloucester maintain impressive Aviva Premiership Rugby momentum heading into two weeks of Anglo-Welsh LV= Cup action. But although Leicester left the west country with a losing bonus point, they still have not won on the road in Aviva Premiership Rugby combat since April.
Both teams went at it hammer and tongs, and while the skill factor never threatened to hit overdrive, fearless commitment ensured a gripping encounter for a crowd of just under 14,000. And the victory means Gloucester have now won their past 16 matches in all competitions, a sequence stretching back to November 8th, 2009 when LV= Cup visitors Cardiff Blues toppled them.
Number eight Luke Narraway captained Gloucester with Mike Tindall on England duty – Jonny May replaced Tindall in midfield – while Narraway's back-row colleague Brett Deacon faced his former club. Leicester were minus England quartet Toby Flood, Ben Young, Dan Cole and Tom Croft, but Jordan Crane returned on the bench following a pre-season ankle injury, where there was also a place for loan scrum-half signing Jason Spice.
Deacon's outing against the Tigers though, lasted just 17 minutes as he was forced off injured during a fast and furious opening. Twelvetrees kicked Leicester into an early lead that Robinson cancelled out just five minutes later, before Leicester's fly-half restored the advantage with another penalty.
Peter Buxton replaced Deacon, but despite both teams making plenty of errors, there was admirable intent and no little skill on show. It was the final pass that went to ground on a handful of occasions, and in terms of scoring contributions, the boot dominated.
A second Robinson penalty made it 6-6, and although he then missed two chances in quick succession, a superb strike from halfway by the Welshman gave Gloucester a three-point interval advantage.
Gloucester's forwards began the second period in determined mood, establishing promising field position, but Robinson missed a resulting penalty chance, leaving him with a 50% strike-rate from six attempts. The home side increasingly looked to free dangerous wing Charlie Sharples in space, and his darting breaks created sufficient problems for Tigers' defence to force another penalty that Robinson landed.
Leicester knew they needed a quick response, and after they noticeably increased the tempo, Twelvetrees completed his penalty hat-trick when Gloucester infringed just 25 metres out.
It was tight, tense and attritional, with no obvious sign of a winner entering the final quarter as Gloucester introduced their firebrand French hooker Olivier Azam off the bench. Twelvetrees tied the game 17 minutes from time, but with Azam's fellow substitute Vainikolo also joining the action, Gloucester possessed an enhanced attacking thrust.
Leicester continued to give as good as they got, with number eight Thomas Waldrom repeatedly surging over the gain-line and keeping Gloucester's defence honest. Vainikolo, cleverly used as powerful runner through midfield channels, almost powered over for a try with eight minutes left.
He was hauled down short of the line, but Smith was yellow-carded for killing possession, only for Robinson to miss a gilt-edged penalty chance from 30 metres. Gloucester lock Jim Hamilton then followed Smith to the bin after an off-the-ball incident, yet Vainikolo came up trumps when it mattered, and the home side could start celebrating another important win.