With the points of no major value to either side bragging rights proved the major motivating factor at Dooradoyle last night which had a delayed start as the game was moved from the grass to the astro-turf surface, the first occasion it was used for an AIL game.
Garryowen held out for a deserved win as Young Munster plunged to their fifth defeat in a row.
Young Munster made a splendid start when their pack set up a rolling maul and hooker Ger Slattery got in for a try that Derry O'Connor converted.
That was after only six minutes but the home side hit back with a try. It followed a period of constant pressure and Eamonn Connolly touched down and Matt Jarvis tied it up with the conversion.
Slattery was sin-binned after 20 minutes and for the first time Garryowen hit the front with a penalty by Jarvis and they never lost the lead. They had a second try before the interval, this time by Dave Sherry, which Jarvis again converted to leave it 17-7 at the interval.
A superb try by Shane O'Leary, converted by O'Connor, raised Young Munster hopes but Jarvis kicked a second penalty to ensure the win for Garryowen.
Scorers Garryowen: Eamonn Connolly, David Sherry tries, Matt Jarvis 2 pens 2 cons.
Young Munster: Ger Slattery, Shane O'Leary try each, Derry O'Connor 2 cons.