Clearly, the champions were eager to stamp their authority early, simply refusing to bow to the conditions using power and passing to move onto the front-foot.

A devastating attack, began by captain Max Kearney, was topped by scrum-half Paraic Cagney’s no-look pass to wing Mark Donnelly for a superb try converted by full-back Hugh O’Sullivan in the second minute.

It was already looking like a long afternoon in the rain for St Andrew’s as they tackled low and hard. Centre Peter Sullivan cleared his lines to stem the torrent.

Leinster Schools Senior Cup

When the Booterstown school did find relief from Aaron O’Neill’s penalty to touch, Kearney led the wrap-up and hold-up on Sullivan for a scrum turnover.

The set-play put O’Sullivan on the ball in midfield and the full-back simply sizzled through the first line to find try-scorer Cagney with a sweet inside pass and convert for 14-0 in the 10th minute.

St Andrew’s were living off scraps even though a thunderous hit by their number eight Zola Henry was met with an instant uplift.

The greasy ball began to fall from Belvedere hands and they also incurred the wrath of referee Gary Glennon at the scrum and breakdown.

Leinster Schools Senior Cup

Still, the incisive surge from O’Sullivan required muscular defence from flanker Stephen Keane.

Then, centre Sullivan swallowed up David Hawkshaw’s chip and countered strongly.

Hooker Harry McCarthy’s half-break was taken on by Keane. They looked to be in business until Max Kearney took charge of the ruck.

Unfortunately, St Andrew’s were behind their posts again when lock Ben Crowley couldn’t hold onto the ball and Donnelly snapped it up for a clinical finish for 19-0 in the 31st minute.

Leinster Schools Senior Cup

The jet-propelled rush of Belvo’s defence was problematic for a static attack as St Andrew’s captain McCarthy and the outstanding Henry tried everything they knew.

The holders were going through the gears again when Sullivan picked off an interception on halfway to ghost home to delirious approval from the stands.

Centre Nathan Fitzpatrick-Couzy converted to bring the game back to life.

The Great Denmark street school took this sting well enough to create openings, mainly through left wing Jordan Wilkes.

They moved into position and kept their patience for lock Oran O’Brien to go low for the line.

O’Sullivan converted to re-establish their superiority in the 49th minute.

Leinster Schools Senior Cup

Belvo’ were able to open up the route to a second strike direct from a scrum when number eight Ruadhan Byron arced around one defender and through another for 31-7 in the 54th minute.

No sooner had Harry Beggy entered the game as a replacement than he was hurtling towards the posts for O’Sullivan to tie on a conversion.

The eagle-eyed Donnelly profited from a miscommunication to complete his hat-trick in the 66th minute.

Fly-half Hawkshaw made it eight tries-to-one when countering at speed to close the show.

Belvedere College 48 St Andrew’s College 7

At Donnybrook – BELVEDERE COLLEGE 48 (M Donnelly 3 tries; H Beggy, P Cagney, O O’Brien, R Byron, D Hawkshaw try each; H O’Sullivan 4 cons); ST ANDREW’S COLLEGE 7 (P Sullivan try; N Fitzpatrick-Couzy con).

Belvedere: Hugh O’Sullivan; Mark Donnelly, Peter Maher, Cian Walsh, Jordan Wilkes; David Hawkshaw, Paraic Cagney; Cillian Molloy, Sam Osborne, Jake Robinson, Grellan Murray, Oran O’Brien, Max Kearney (capt), Conor Doran, Ruadhan Byron.

Replacements: Conor Byrne for Osborne, David Hill for Doran both 54 mins; Harry Beggy for Walsh 60 mins; Anthony McDonnell for Molloy, Joseph Haughey for Robinson, Jamie O’Grady for Maher, Gregory Petherbridge for O’Sullivan all 63 mins.

St Andrew’s: Andrew Vincent; Daragh Geraghty-Singleton, Peter Sullivan, Nathan Fitzpatrick-Couzy, Reece Jordan; Aaron O’Neill, Will Hennessy; Patrick Murray, Harry McCarthy (capt), David Wilson, Ben Crowley, Daniel O’Connell, Stephen Keane, Rory Simington, Zola Henry.

Replacements: Hugh Black for O’Neill 31 mins; Nicholas Judge for Simington, Jack O’Brien for Murray both 51 mins; Patrick Perrem for O’Connell 54 mins; David Molloy for Vincent 60 mins; Luhle Sigcau for Geraghty-Singleton 63 mins; Roan Kennedy for Wilson 65 mins.

Referee: G Glennon, Leinster Branch.