A Spectacular try to second-rower Jarrad Kennedy seven minutes into golden-point extra time gave Canberra a thrilling 28-24 victory over Brisbane in the U20 rugby league grand final at ANZ Stadium.

Kennedy was mobbed by jubilant Raiders teammates after collapsing over the line in exhaustion after willing himself to back up centre Jarrod Croker, who had collected a cross-field kick from halfback Matt Smith as the clock wound down.

Canberra won the hard way, though, recovering from 20-12 down early in the second half and then needing a missed conversion attempt from Broncos halfback Ben Hunt to force extra time.

Gunning for their eighth straight victory, Brisbane made a worrying start, conceding a soft try to five-eighth Michael Picker, which fullback Josh Dugan converted for a 6-0 lead after 10 minutes.

A second try to Michael Picker and a goose-stepping four-pointer to winger Drury Low, plus Dugan's heroics, eventually set the scene for Kennedy's match-winning play.