Garryowen moved up one place to fifth in Ulster Bank League Division 1A after claiming the scalp of Cork Constitution at Temple Hill on Saturday.
An opportunist try from winger Alan Gaughan just before half-time was the decisive score as the Light Blues lifted the Trevor Barry Memorial Cup.
Cork Constitution were also beaten at home by Garryowen's Limerick rivals Shannon recently, so this result will further dent their title ambitions.
They defended the clubhouse end in the opening half with a wind blowing diagonally across the pitch favouring neither team.
Garryowen out-half Declan Cusack watch his ninth minute penalty drift to the left of the posts. Scoring chances were few and far between and both sides were guilty of kicking away good possession.
This scrappy encounter looked set to be scoreless at the break until a mix-up in the Constitution rearguard saw Gaughan swoop on a fumbled ball near the home 22 and score the only try.
Fergal Lawlor added the conversion for a 7-0 advantage and the seven-point margin was still in place when Gerry Hurley and scrum half Lawlor swapped penalties early in the second half.
Try scorer Gaughan fired over a 58th minute penalty to strengthen Garryowen's hand and although Ronan O'Mahony was sin-binned and Hurley closed the gap with two more successful kicks, Cork Con's only reward was a losing bonus point.
Garryowen controlled possession for the last few minutes to see out their second significant away victory of the current campaign.
Referee: Peter Fitzgibbon (IRFU)