Garryowen chalked up their second league win with a determined display at Anglesea Road.
The Garryowen forwards held the edge over a Belvedere pack that contained three Under-20 players and Conor Kilroy and company took advantage on the scoring front.
The sides swapped tries through Ciaran O'Boyle (11 minutes) and Felix Jones (14) meaning Belvedere were only 14-11 behind at half-time.
Out-half Kieran Hurrell kicked them level but Garryowen seized control for the remainder, with Anthony Kavanagh (53) and O'Boyle (59) tagging on decisive tries.
Old Belvedere: Try: Felix Jones; Pens: Kieran Hurrell 3
Garryowen: Tries: Ciaran O'Boyle 2, Anthony Kavanagh; Con: Conor Kilroy; Pens: Conor Kilroy 2; Drop: Willie Staunton
