Replacements: Paddy Hogan, Adam Howard, Colin Mallon, Dylan Simmonds, Fergal Lawlor.
Replacements: Peter Weir, Toby Mannus, James McBriar, Matthew Nelson, Stuart Orr.
Out-half Steve Crosbie's penalty from the left wing was well short of the target, however, much to the relief of Ballynahinch - who have had to use a total of 36 starters to date in the current campaign for a variety of reasons.
The hosts continued to dominate possession during the opening ten minutes, but 'Hinch soon settled into their stride and raced into the lead when Ulster's David McIlwaine finished off a fine move up the field by the County Down outfit.
Full-back Richie Lobb was on hand to expertly kick the conversion off a low trajectory, which offered them an excellent early platform against 'Belvo.
Their lead did not last long though, as a terrific move across the 'Hinch line was finished off in the left corner by 'Belvo's dynamic full-back and captain Daniel Riordan.
Crosbie's conversion kick was from a similar angle to his first effort, but he was able to find his range on this occasion which restored parity at 7-all.
This proved to be a confidence-building score for the 2011 league champions, who crossed the whitewash once again on the 20-minute mark. The momentum of bustling second row Josh Eden-Whaitiri enabled him to reach over on the right flank following a neat offload by Crosbie.
The Ireland Under-20 International was wide of the mark from his second conversion attempt and with Lobb superbly slotting a 30-metre penalty between the posts four minutes later, there was only two points separating teams.
'Belvo had been somewhat ill-disciplined when it came to conceding penalties in the opening period, but 'Hinch were equally guilty in this regard.
A brace of Crosbie penalties in the 34th and 38th minutes gave the Ballsbridge brigade an eight-point cushion heading into the closing stages of the half, but they were hit with something of a sucker-punch just before the interval.
Ballynahinch captain Stuart Morrow found a gap through the heart of the 'Belvo rearguard, and he emphatically touched down underneath the posts for a try that was comfortably converted by the reliable Lobb.
This ensured that the hosts' lead was down to the bare minimum (18-17) as the action resumed, and even though the visitors were briefly down to 13 players as a result of yellow cards issued to Michael Cromie and Paul Pritchard, last season's Division 1B victors regained the lead courtesy of another routine Lobb three-pointer 48 minutes in.
Yet, after some shaky moments upon the resumption, Old Belvedere were able to find their feet again. After a long spell of possession inside the 'Hinch 22, flanker Jack Conan drove over for his side's third try approaching the hour mark.
With Crosbie tagging on the extras, 'Belvo were back in the ascendancy and it seemed like only a matter of time before the inevitable bonus point try arrived.
The outstanding Riordan duly delivered this vital score for Paul Cunningham's charges after 56 minutes, as his magnificent individual run on the right wing was finished off with style and aplomb.
Crosbie came up short from his final strike at goal of the day, and with Lobb once more clipping over a close range penalty 14 minutes from the end, there was still an outside chance that 'Hinch could snatch victory from the jaws of defeat.
The contentious 75th minute sin-binning of Riordan was a setback for 'Belvo in the latter stages and when Lobb swiftly increased his personal haul to 16 points, a gripping finale was in store.
Indeed, Ballynahinch did their utmost to try and secure the score that would give them their first top flight victory of the 2013/14 season, but strong defensive work meant that Old Belvedere held on for a hard-earned success.
Referee: Gary Conway (IRFU)