Bristol snuffed out any advantage Gloucester might have stolen from Leicester's defeat at London Irish, winning 29-26 at the Memorial Ground in the Guinness Premiership on Sunday.
Jason Strange inspired Bristol to their victory with an immaculate display of goalkicking.
Although Gloucester edged the try-count 3-2 during an absorbing west country derby, Strange's relentless accuracy proved decisive.
The fly-half booted a drop goal, four penalties and two conversions for a 19-point haul that grounded Gloucester.
It was Gloucester's fourth defeat of the Premiership campaign, yet they had looked in control after scoring three tries during the opening 27 minutes.
Scores by wing James Simpson-Daniel, plus centres Jack Adams and Anthony Allen, appeared to put the visitors in control at 17-9 ahead.
Bristol though, struck with touchdowns of their own by hooker Scott Linklater and prop Jason Hobson just before the break that carved out an interval lead.
And despite clear-cut scoring chances proving at a premium after the break, Strange, whose late drop-goal won the corresponding fixture last term, ensured Bristol stayed ahead.
There was a fraught finale for the home fans as Gloucester substitute Willie Walker scored penalties in the 71st and 73rd minutes, yet Bristol retained their composure to play down the clock expertly.
Bristol's victory takes them well clear of 11th-placed Worcester, while Gloucester remain at the summit following second-placed Leicester's defeat at London Irish.
Bristol, unbeaten at home since mid-September, went into battle with England hooker Mark Regan on the bench, but Gloucester included red rose trio Iain Balshaw, Lesley Vainikolo and Luke Narraway in their starting line-up.
And it was Gloucester whose early rugby matched the winter sunshine as they posted two tries in as many minutes after a Strange penalty double hoisted Bristol 6-0 ahead.
Simpson-Daniel claimed the opener when he rounded off a midfield break by Adams, and the wing then turned provider through a kick and chase that ended with Adams touching down.
Scotland star Chris Paterson, the World Cup's most accurate marksman, missed both conversion attempts, but Gloucester then matched a third Strange penalty by claiming another try.
Strange turned villain for Bristol, firing an ambitious pass on the halfway line that Allen gratefully accepted and sprinted 50 metres to score, with Paterson adding the extras.
Trailing 17-9 and with Gloucester in sight of a try bonus point, Bristol could have folded, yet their response stunned the league leaders.
Opting to utilise their renowned strength - forward power - Gloucester leaked close-range tries either side of their skipper Marco Bortolami being sin-binned for pulling down a maul.
Linklater scored the first, profiting from a superb lineout take and drive by lock Roy Winters, and Strange's conversion brought Bristol back to one point adrift.
Bortolami then departed, giving Bristol enough time to take an unexpected interval lead when Hobson, who was on England replacement duty in Rome last Sunday, ploughed over.
Gloucester head coach Dean Ryan waited in the tunnel to read his team a half-time riot act as Strange converted, making it 14 unanswered points in six minutes.
And there was no immediate sign of a Gloucester recovery early in the second period after Strange and Paterson exchanged penalties.
Both teams tightened up defensively, closing down space, but Bristol exerted a prolonged territorial grip on the contest, pinning Gloucester deep inside their own half for much of the third quarter.
Ryan made liberal use of his substitutes to try to revive Gloucester's challenge, but it looked over when Strange slotted a drop-goal 14 minutes from time.
Walker though, who replaced a largely subdued Paterson, had other ideas as he landed two penalties in quick succession that reduced the gap to 29-26.
Bristol had to regroup as pressure mounted from their opponents, yet experienced heads like Strange, skipper Matt Salter, number eight Andrew Blowers and the outstanding Linklater ensured the prize of a notable victory was not allowed to slip away.
Tries: Linklater, Hobson
Cons: Strange 2
Pens: Strange 4
Drop goal: Strange
Tries: Simpson-Daniel, Adams, Allen
Pens: Paterson, Walker 2
Bristol: 15 Luke Arscott, 14 Lee Robinson, 13 Rob Higgitt, 12 David Hill, 11 David Lemi, 10 Jason Strange, 9 Brian O'Riordan, 8 Andrew Blowers, 7 Joe El Abd, 6 Matt Salter, 5 Sean Hohneck, 4 Roy Winters, 3 Jason Hobson, 2 Scott Linklater, 1 Darren Crompton.
Replacements: 16 Mark Regan, 17 Alex Clarke, 18 Gareth Llewellyn, 19 Alfie To'oala, 20 Graeme Beveridge, 21 Sam Cox, 22 Josh Taumalolo.
Gloucester: 15 Iain Balshaw, 14 James Simpson-Daniel, 13 Jack Adams, 12 Anthony Allen, 11 Lesley Vainikolo, 10 Chris Paterson,9 Gareth Cooper, 8 Gareth Delve, 7 Andy Hazell, 6 Luke Narraway, 5 Will James, 4 Marco Bortolami (capt), 3 Carlos Nieto, 2 Jeremy Paul, 1 Nick Wood.
Replacements: 16 Andy Titterrell, 17 Alasdair Dickinson, 18 Peter Buxton, 19 Alasdair Strokosch, 20 Rory Lawson, 21 Willie Walker, 22 Mark Foster.
Referee: Wayne Barnes
Touch judges: Ashley Reay, Paul Emerson
Television match official: Brian Abrahams