Guilford Young College came from a 14-point half-time deficit to overrun competition heavyweights St Patrick's College in the SATIS grand final.
Lincoln Arnold kicked his second major after the full-time siren at Kingston to put the icing on a 9.9 (63) to 6.5 (41) victory and seal Guilford's first flag since 2002.
With star St Patrick's forward Jackson Callow missing with injury, Clarence young gun Noah Holmes dominated at the other end to kick a match-winning five goals with fellow Roo Darcy Gardner also impressive.
Angus Jefferies and Zach Morris (one goal apiece) and Michael Stingel were among St Patrick's best with Declan Chugg (two), Bailey Gillow and Oliver Chugg also hitting the scoreboard.
Guilford also made a stunning comeback when the two sides met earlier this year, kicking the last five goals of the game to win by seven points.
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