London Welsh booked a quickfire Aviva Premiership return after condemning big-spending Bristol to another season in English rugby's second tier.
The Exiles took a 19-point advantage with them into the Championship final second leg, and Bristol - despite being roared on by an 11,000 Memorial Stadium crowd - never seriously threatened to wipe out that deficit as Welsh prevailed 21-20.
Bristol were not helped by fly-half Nicky Robinson missing three penalties and two conversions, with tries by wing Andy Short, number eight Mitch Eadie and substitute Adam Hughes - plus a Robinson penalty and Adrian Jarvis conversion - proving insufficient.
Exiles flanker Carl Kirwan and wing Seb Stegmann scored late tries and fly-half Gordon Ross slotted 11 points through a drop-goal, two penalties and a conversion, securing a place back in the Premiership as replacements for relegated Worcester.
It represents a huge triumph for a club who dropped out of the top flight last term when they fell away following a points deduction for fielding an ineligible player.
But coach Justin Burnell has masterminded a brilliant recovery and they will now once again rub shoulders with the likes of Northampton, Saracens and Leicester next term.
Bristol, despite having signed a host of new players for next season including Ryan Jones, Dwayne Peel, Anthony Perenise and Matthew Morgan, will remain in the Championship.
While Welsh celebrated landing the Championship title, Burnell's opposite number Andy Robinson must now galvanise Bristol for another promotion push, although their cause will not be helped by Worcester's presence.
Robinson made four changes after a crushing defeat at the Kassam Stadium last week, with Charlie Amesbury, Ruki Tipuna, Gaston Cortes and Eadie all handed starts. Eadie replaced Wales number eight Jones, who suffered a serious ankle injury seven days ago.
Welsh welcomed back flanker Mitch Lees for his first appearance since mid-April, with full-back Alan Awcock also called up and Stegmann moving to the wing.
Bristol's final game at a ground that has been their home since 1921 - they will play at Ashton Gate next season - needed to start with maximum intensity from their point of view.
And Andy Robinson's men blasted out of the blocks, pinning Welsh inside their own 22 through a succession of advances by their major ball-carriers, but goalkicking let them down.
Nicky Robinson missed two penalty chances in the opening 12 minutes as both packs got to grips with each other through legal and illegal means, but Welsh weathered the storm and gradually gained a territorial foothold.
Ross and centre Tom May showed all their experience by kicking sensibly into the corners, with Bristol's frenzied opening producing nothing in terms of where it mattered most - on the scoreboard.
Ross then punished them through a 27th-minute drop-goal that extended Welsh's aggregate advantage, only for Bristol to reply with a well-worked try when Robinson sent a pinpoint kick into Short's arms and he finished off in the corner.
A Ross penalty restored the visitors' advantage and then it was all hands to the pump when Exiles scrum-half Chris Cook received a yellow card for a deliberate knock-on.
Bristol could not capitalise by scoring a second try but Robinson finally hit the target when his fourth kick of the night sailed between the posts to secure an 8-6 interval advantage.
And it got better for the home side within three minutes of the restart when a well-worked lineout move resulted in Eadie charging 30 metres for a try that revived Bristol's dream.
Robinson's fourth miss from five attempts off the kicking tee meant it stayed at 13-6, though, and his inaccuracy was starting to add up as 10 points had gone begging that meant Welsh still enjoyed a relatively comfortable overall advantage.
Robinson then sent another penalty wide, and that was to be his final act as he made way for Jarvis with 23 minutes left.
Hughes scored a try to give Bristol renewed hope, but it was not to be, and Welsh began wild celebrations after Kirwan and Stegmann touched down in rapid succession as the curtain fell on another English domestic season.