Chapman, from North Narrabeen, defeated Matty King (AUS) (13.55) Kanoa Igarashi (USA) (11.65) and Jackson Giles (AUS) (8.35) in the four-man final.

The last remaining local surfer, Kurtis Herman, was knocked out in the quarter-finals.

At just before 6.30pm - nearly three hours after the final was originally scheduled - Chapman, a 19-year-old natural-footer, ripped apart wave mush at The Cliff, some 500 metres north of the Merewether contest site.

Organisers were hampered by a lack of swell at Merewether and had to wait until the completion of the international trials at The Cliff.

Chapman's dominance in the final was stamped inside the first minute of the heat when he scored a 9.75 (out of a possible 10) and he followed that with 7.25 just three minutes later.

■ WEST Australian Bronte Macaulay won the junior women's competition in small, clean waves.

In a final played out in a light offshore wind, Macaulay (16.25 out of a possible 20) defeated Holly Wawn (13.9 out of a possible 20) from Sydney's northern beaches.

Macaulay tied her quarter-final heat with Kingscliff's Ashlee Spence, but Macaulay progressed because she had the highest wave score in that heat.

"I don't think they were the smallest waves I have surfed in a comp but they might have been the slowest," she said.

Macaulay was rewarded with a 9 (out of 10) for her effort in the final.