Replacements: Aaron Ferris, Jamie Kirk, James McBriar, Conor Piper, Chris Stevenson.
Replacements: Evan O'Sullivan, Gavin Ryan, Ger Burke, Sean Upton, Shane O'Brien.
A solid scrum produced good first phase ball where full-back Rodger McBurney ran a great line to break clear and feed inside to winger David McIlwaine who dived over at the posts. Richie Lobb added the extras for a 7-0 lead.
In the 15th minute flanker David McGuigan turned over ball in the 'Hinch 22 and burst clear, racing upfield where he was eventually caught five metres short of the Munsters' line.
The quick ball was released right where McBurney was on hand to charge through and score the second 'Hinch try. Lobb converted to leave the Cookies 14-0 behind.
Ballynahinch then lost the services of tighthead prop Chris Taylor who had to retire with an injury in the 23rd minute, with the experienced Chris Stevenson coming on in his place.
Young Munster got themselves on the scoreboard in the 30th minute when 'Hinch were peanalised for coming in at the side of a ruck. Scrum half Brian Haugh stepped up to nail the three-pointer.
The visitors pressed again after Stevenson was yellow carded in the 28th minute for repeated infringements in the scrum.
But, as the first half drew to a close, the home side took control again to keep Young Munster on the back foot. Lobb landed a penalty goal to put 'Hinch 17-3 in front at the break.
Now with the wind at their backs, the County Down outfit kept he pressure on the visitors' defence with some accurate kicking from scrum half Aaron Cairns, Lobb and McBurney.
The third 'Hinch try came in the 58th minute when Willie Staunton's clearance kick was fielded near the touchline by Lobb who immediately counter-attacked, beating one defender and then passing inside to McBurney in support.
The 'Hinch full-back cleverly chipped the cover defence, collected the ball and won the race to the corner. Lobb converted the try - with the aid of the left hand upright - for a 24-3 scoreline.
Prop Kyle McCall was yellow carded in the 62nd minute for overuse of the boot at a ruck close to the 'Hinch line, but a great steal from lock Jonny Madden in the 68th minute managed to release the pressure and clear the danger.
The vital bonus point try arrived soon after. With McCall in the sin-bin, the scrums went uncontested. 'Hinch had forced a kickable penalty on the edge of Limerick side's 22 and opted for the set piece.
Cairns flashed the ball wide where great hands from the 'Hinch back-line created just enough room for McIlwaine to beat Barry Gibbons on the outside and finish well in the corner for an unconverted try.
Ballynahinch skipper Stuart Morrow was the creator of the final try in the 74th minute when he smashed his way past Staunton and through a gap in the Munsters' midfield.
As the 22 approached, Morrow passed inside to put replacement full-back James McBriar clear and he dived in under the posts. McBriar added the conversion to complete the scoring at 36-3.
Ballynahinch scrum half Cairns excelled for the victors on the day. He was in the thick of the action - if he was not on the ball, he was chasing kicks or leading the hosts' defencive line.
Two other stand-out players were try scorer McBurney and openside McGuigan, who both contributed a great deal to the quality of this game.
Speaking afterwards, Ballynahinch head coach Derek Suffern said: "The boys are ecstatic in the changing room, we have been waiting a long time for this result.
"We thought it had come two or three weeks ago, but the boys kept getting kicked when they think they are over the line, and they have shown great, great character.
"We have had a super week in training and the boys played really well today, and scored some great tries and I thought our all round performance was superb.
"We have been working hard on just trying to do simple things right. We had a few simple plays that we looked at during the week.
"The opening score set the tone and it is excellent when a play is executed well. It was a good scrum, a good eight to nine and Rodger (McBurney) broke the line - he had a super game - and then put McIlwaine away.
"Our desire to win is right up there and that was typified in the boys' reaction at the final whistle when the game finished on an error of ours. The boys were unhappy at that mistake and were not jovial enough at the end having secured all five points.
"I suppose it shows they know where they are, and what they have to get - they were craving points difference in the game and it shows what it means to them and what it means to the club that the boys are prepared to fight for every single thing they can get on the pitch."
He added: "This coming week we are at Cork Constitution and the boys have got to take a lot of confidence from this result, so we have go down there and get our basics right, get our attacking game going and make sure we are nice and disciplined and physical in defence.
"If we can do that I think we have a great opportunity to get over the line again."
Referee: Gary Conway (IRFU)