A bitterly cold and strong cross field wind mixed with heavy showers made conditions difficult in this Munster Schools Junior Cup tie which was switched from Clanwilliam to Annacotty.
Despite this both sides coped well and the difference between them at the end was the opening penalty for Castletroy after 25 minutes by Conor Fleming.
Both sides had a try by their No 8, both had a player sin-binned at different stages of the second half and both missed good scoring opportunities.
After several drives Castletroy finally had a try when David Rowsome squeezed in at the corner in the last play of the first half.
Glenstal squandered scoring chances in the second half including opting for touch from a couple of penalties but they were rewarded for a plucky display when the outstanding George O'Hara raced in after persistent pressure.
Castletroy had good performers in Jack O'Mara, a nephew of Peter Clohessy, Evan Slattery and Rowsome with
Conor Fleming and Jamie Heuston a sold halfback combination.
Glenstal had excellent backs in Jack Stafford, Charles Gavin and especially Gordon Daly with James Enright and Theo Broderick doing well in the pack.
Glenstal Abbey: Killian Glynn; Sean O'Sullivan, Charles Gavin, Tim Costigan, Gordon Daly; Jack Stafford, Colm Hogan; Luke Lynch, Johnny Williams, David Quane; Theo Broderick, Alex Donohue; William Murray, James Enright, George O'Hara. Replacements: Rory Johnston for Glynn, Darren Halpenny for Enright.
Castletroy College: Oisin Kelly; Shane Hogan, Ronan McDonnell, Colum Carroll, Sean McBrearty; Jamie Heuston, Conor Fleming; Joey Conway, Mark O'Mara, Conor Myres; Evan Slattery, Eoin Hourigan; Luca Ridder, Niall O'Shea (capt), David Rowsome.Replacement: Kevin Davern for Ridder
Referee: D Sheehan, MAR