Replacements: Daniel Montgomery, Evan Ryan, Mike Madden, Sean Upton, Greg Barry.
Replacements: James McBriar, William Richards, Jordan McMullan, Chris Taylor, Andrew Harper.
The home supporters were in great voice in the 13th minute when winger Lukas Kunz, the former Garryowen player, raced clear from distance to touch down.
By half time wind-backed Young Munster led 19-6 thanks to the first of two tries by Kunz's wing colleague Derry O'Connor. Ballynahinch out-half Lobb had kicked a second penalty when Young Munster were penalised in a scrum.
Persistent early pressure in the second half led to a 'Hinch player being sent to the sin-bin for a deliberate foul as the home side swarmed near the line.
The Cookies were rebuffed on that occasion but splendid work by centres Dan Goggin and Kolio Hifo sent O'Connor in at the corner for his second touchdown.
It was then Young Munster's turn to have a player sent to the bin - prop Alan Cotter picked up a yellow card - but after 68 minutes their number 10 Shane O'Brien made the most of a very lucky bounce to take off from far out for a final but precious fourth try.
'Hinch's only consolation was a late try from replacement James McBriar, and they will be hoping to bounce back away to St. Mary's College in three weeks' time.
Referee: Nigel Correll (IRFU)