A moment of genius from St Gerard’s captain Cormac Foley was all that separated two well-matched schools in the Bank of Ireland Leinster Schools Senior League final at Donnybrook on Thursday.

There was almost a try from the kick-off when Gonzaga wing Arthur Henry took advantage of a slip from the first man up to head off for a gain of 60 metres until shepherded into touch by a closing defence.

Henry joined in the next attack for go-forward and out-half Hugh Gleeson tickled a kick over the top.

From there, hooker Eoin Barron pinched a lineout and lock Eoin Buggy made metres.

St Gerard’s were not flustered, getting their act together out of touch for scrum-half Jack O’Caoimh to clear his lines.

It spoke to their defence that they spent all of the opening 10 minutes in their own half under pressure from a bigger side with their captain Foley, lock Daniel McGovern and loose forwards Donal Ahern and Rory Wilson making tackle after tackle on ball-carriers.

Their wing Morgan Freeley was twice dominant in the air and fly-half David O’Brien almost got away down the right.

Back came Gonzaga, flanker Jack Barry making an incision and Buggy following up to force a penalty for offside, scrum-half Jack Connolly splitting the posts for 3-0 in the 18th minute.

St Gerard’s Foley was into everything, forcing turnovers and, on occasion, showing up as first receiver.

They forced a penalty at the ruck for centre Oliver Haydock squared the game in the 26th minute.

They were back for more from a smooth move right to left and the sprinting speed of wing Paddy Opperman was denied by an unkind bounce of the ball from his own chip.

The game was balancing out as St Gerard’s started to look more comfortable in their game plan.

St Gerard’s were able to sustain enough pressure to draw a penalty for Haydock to nudge them ahead just before the break.

It was ding-dong as Gonzaga centre Brian O’Donnell’s clever ball in behind had to be rescued by scrum-half Jack O’Caoimh.

Just when another monster tackle from Foley looked to have stemmed the tide, ‘Zaga number eight Robbie Kidney slipped through a seam in the defence for the first try in the 46th minute.

The pressure coming from fierce defence placed a premium on skills.

Then, O’Donnell’s in-to-out movement got him through the first line before timing the pass to put full-back Frank O’Grady over on the right for 13-6 in the 53rd minute.

They were nearly in again when wing Daniel Inglis was called back for a foot in touch.

St Gerard’s were able to receive these body blows and strike back in stunning fashion from inside their own half.

Full-back Max O’Reilly got around the outside to kick over the top for Foley to win the race for the ball on the hour to narrow the gap to two.

Gonzaga centre Eoin Barr was twice able to kill St Gerard’s momentum with picture perfect turnovers as the mistakes began to creep up in a pulsating final quarter.

It took one piece of brilliance from Foley to make the difference, weaving his way through from halfway for a last play victory try, converted by Haydock.

At Donnybrook – St Gerard’s School 18 (C Foley 2 tries; O Haydock 2 pens, con); Gonzaga College 13 (R Kidney, F O’Grady try each; J Connolly pen)

St Gerard’s: Max O’Reilly; Morgan Freeley, Oliver Haydock, Cormac Foley, Paddy Opperman (Jack Kennedy 57); David O’Brien (Ben Watson 53), Jack O’Caoimh; David Carroll, Robert Byrne, Adam O’Reilly, Niall Dooley (Thomas Cahill-Hannigan 62), Daniel McGovern, Donal Ahern, Charles Byrne, Rory Wilson.

Gonzaga: Frank O’Grady; Daniel Inglis, Brian O’Donnell, Eoin Barr, Arthur Henry; Hugh Gleeson, Jack Connolly; Michael Gleeson (Henry Godson 60), Eoin Barron, Simon Clear, Caoilim Fassbender, Eoin Buggy, Ian O’Grady, Jack Barry, Robbie Kidney (capt).

Referee: Berney White, Leinster Branch