City eased to victory on their first ever visit to Stevenage to send their hosts crashing down to Sky Bet League Two.
Goals from Wade Elliott, Sam Baldock and Stephen Pearson sealed the fate of the home team just two years after they were beaten in the League One play-offs.
Luke Freeman’s late free kick spoiled hopes of back-to-back away clean sheets, but did nothing to detract from the party atmosphere at one end of the Lamex Stadium.
Steve Cotterill made three changes to his side fortunate to escape with three points against Stevenage’s fellow strugglers Notts County on Good Friday.
Tyrone Barnett was handed his first start in two months alongside the division’s leading marksman Baldock, with Jay Emmanuel-Thomas dropped to the bench and Martin Paterson left out completely as the unlucky sixth loan player.
Elsewhere, there were recalls for Brendan Moloney and Simon Gillett, as Scott Wagstaff took his seat among the substitutes.
With the hosts desperate for a win in their fight to avoid the drop, it was City who created the first chance.
As Baldock sneaked in behind the defence unopposed, his square pass towards Barnett was cut out but rolled invitingly back into his path for a first time shot well saved by Chris Day at his near post.
It would prove a busy opening to the game for Day, who denied Baldock again with his legs soon after, before Derrick Williams’ header was blocked on the line by a keeper making his third decent save inside the first nine minutes.
But Baldock remained the most likely, again coming close when meeting Greg Cunningham’s cross with a header only carried wide by a slight deflection.
It was all City, with Baldock intent on adding to his 23 league goals sooner rather than later.
The skipper found himself clean through when Barnett’s knockdown invited a piercing first-time pass between the centre-backs for Baldock to run on to and shoot low against the legs of Day.
The visiting trio combined again when Baldock’s pass preceded an Elliott cross glanced on by Barnett towards the bottom corner, where Day was again on hand to preserve an unlikely clean sheet.
It was a first half City had total control of, finally getting the lead their dominance deserved three minutes before the interval.
This time Baldock dropped deeper to initiate the attack with an excellent sweeping pass out to the right, which Moloney collected on the run and crossed low for Elliott to convert at the far post.
There was still time for a similar opening to present itself before the half-time whistle sounded, as another Moloney cross was missed by Baldock at the near post before Cunningham struck the side-netting from a difficult angle.
The hosts finally posed a threat in stoppage time, as Peter Hartley tried his luck from distance with a powerful shot tipped over by Simon Moore before Luke Jones met the ensuing corner with a header cleared from the goal line by Elliott.
With 45 minutes to save their season, a Stevenage reaction was to be expected.
Substitute Lucas Akins came close with a shot on the turn only to drag the chance wide, but a sustained spell of pressure was not forthcoming.
Instead City doubled their advantage on 66 minutes, as Baldock finally got the goal his day’s work merited.
With the home team piling men forward, Moloney’s flick around the corner left the striker all alone with only Day to beat – this time converting with a low shot under the goalkeeper.
Akins twice came close to halving the deficit, seeing a backheel saved by Moore before a fierce shot struck his own team-mate, before substitute Pearson put the result beyond doubt with a well-taken third.
Within two minutes of coming on, the Scot latched on to Barnett’s pass to run clear and slide the ball past Day and into the bottom corner for his first goal in 17 months.
The talented Freeman curled an impressive free kick into the top corner with five minutes left, but a lack of support from those around him ultimately left Stevenage well short both on the day and throughout the season.