O’Leary, making his first appearance at Ulster Bank League level, added the extras to a last-gasp penalty try as Munsters maintained their winning start to 2013.

This was actually the Cookies’ second successive Division 1A clash with Belvedere whom they beat 40-3 in Limerick last month.

Mike Prendergast’s men were eager for game-time after the postponement of their meeting with Dolphin last weekend, but ‘Belvo led at the break.

Goal-kicking winger Josh Glynn slotted a fifth minute penalty that proved to be the only score of a defence-dominated first half.

Munsters’ top scorer in the league, scrum half Brian Haugh, brought them level with a 53rd minute penalty.

But the Dubliners were back in front just two minutes later as winger Eddie Devitt cut through for an unconverted effort - his third try in two games.

Both sides were reduced to 14 players in a tightly contested finale, Haugh seeing yellow for the visitors and ‘Belvo openside flanker Kieran O’Gorman sin-binned with the Munsters pack close to the try-line.

That vital try eventually came in the dying minutes as the Limerick club forced a penalty try and replacement O’Leary sent over the decisive conversion.

Scorers: Old Belvedere: Try: Eddie Devitt; Pen: Josh Glynn

Young Munster: Try: Penalty try; Con: Shane O’Leary; Pen: Brian Haugh