Rovers and Exeter played out a remarkable game to see out 2022, with the visitors running out 4-3 winners.
The Gas had turned round a two-goal deficit to lead 3-2, thanks to goals from Collins, Coburn and a Sinclair penalty, only for the visitors to come back and snatch the points.
Rovers had made three changes to the starting XI following the defeat at Wycombe - Sinclair, Connolly and Marquis were replaced by Loft, Gordon and Finley. Harry Anderson made a welcome return to the matchday squad.
There was an early penalty shout for the Gas as Coburn tumbled to the floor under a Sparkes challenge, but referee Mather waved away the protests.
Rovers, wearing their away shirt of black and mint, with home shorts and socks, in support of housing charity Shelter, fell a goal behind in the 13th minute as arch-assister Jevani Brown set up Nombe, who curled expertly beyond the diving Belshaw.
Belshaw had to be alert two minutes later as he parried Nombe's shot and Gordon completed the clearance.
Even better was to come from the number one in the 18th minute as he flew across his line to flick Nombe's goalbound header behind for a corner.
Rovers had started the game slowly, and took the opportunity to run to manager Barton for a regroup on the sidelines whilst Exeter's Hartridge received treatment.
Collins saw yellow for simulation in the 25th minute as the referee deemed him to have dived as he latched on to a Thomas through ball.
Sweeney fouled Loft a minute later to present the Gas with a decent position for a free-kick. Evans delivered deep but Thomas couldn't get a touch on it and the visitors remained untroubled at the back.
Rovers continued to be on the wrong of the decisions as Coburn was alleged to have fouled an Exeter defender as he ran clear.
Ryan Loft was then wrestled to the floor but, again, the referee refused to be swayed and the home crowd turned on the official, making for a raucous atmosphere at Rovers' first home evening match of the season.
Diabate was booked for fouling Loft on the edge of the box in the 40th minute. Evans' tame free-kick hit the wall but, from the rebound, the Gas almost equalised, as Collins' close-range header brought a fine save from Blackman.
Caprice was next in the book for time-wasting as he dallied over taking a throw-in in the 45th minute.
In first-half injury time, the visitors doubled their lead after a loose pass from Evans was punished by Archie Collins, who fired home along the ground past an unsighted Belshaw.
Joey Barton responded at half-time by making three substitutions, with Connolly, Sinclair and Anderson replacing Evans, Gordon and Hoole.
Also not coming out for the second half was the away shirt, with the Gas reverting to the more familiar blue and white.
Sinclair was soon in the action, getting to the byline and lofting a ball that had to be scrambled away by the visitors.
From nowhere, the Gas were back in the game. Collins picked up the ball on the edge of the box in the 57th minute and lashed home to halve the deficit.
Brown was booked a minute later for kicking the ball away.
The Grecians wasted two glorious chances to go two goals ahead again, with both Jay and Sweeney shooting wide of the target.
Collins was a man on a mission now after the forward sent in a peach of a cross that Coburn bundled home from close range to make it two apiece in the 64th minute.
Anderson then brought a booking for Sparkes, with the Exeter left-back forced into a shirt pull. Collins was brought down by his namesake, with the Exeter player shown a yellow card in the 71st minute.
The Gas were awarded a penalty in the 74th minute after Collins' run was brought to a crude halt and Scott Sinclair stepped up to slam home the spot-kick.
The Gas were rampant now and, if Coburn was a few inches taller he'd have headed home Finley's clipped cross. Marquis was then presented with a glorious opportunity to settle the game in the 78th minute, as Diabate inexplicably passed the ball straight to him. Blackman saved the defender's blushes.
At the other end, a brilliant Gibson block deflected the ball onto the bar and behind for a corner as the visitors looked to level the scores.
They did make it three-all as substitute Dieng headed in from close range after 83 minutes. Both sides then went for broke, with Stansfield blazing wide of an empty net after rounding Belshaw.
Exeter then went back in front in the final minute as Nombe headed over a stranded Belshaw, who had raced from his line in an effort to intercept a pass. Stansfield wasted a one-on-one chance to make it five in the dying moments, but the visitors held on to claim the points and make it two defeats on the bounce for Rovers.
Next up for Rovers is the visit of Cheltenham Town to The Mem on New Years Day (3pm).
BRISTOL ROVERS: Belshaw, Gordon, Finley, Collins, Coutts, Gibson, Loft, Evans, Hoole, Thomas, Coburn.
Subs: Jaakkola, Connolly, Sinclair, Marquis, Anderson, Whelan, Gibbons.
EXETER CITY: Blackman, Caprice, Sparkes, Hartridge, Jay, Collins, Nombe, Kite, Brown, Sweeney, Diabate.
Subs: Lee, Harper, Stansfield, Key, Dieng, Chauke, Grounds.
Referee: Simon Mather
Attendance: 9,735 (1,167 away)