Apprentice Dylan Dunn has bounced back from a fall on Wednesday to put South Australia into contention for the State of Origin jockeys series.

Dunn rode Binalong Road ($20) who stormed home to win the second heat in the Benchmark 80 (1350m) at Doomben on Saturday.

The win lifted South Australia to 17 points, 16 points behind leaders NSW who finished the day on 33, despite not winning a heat.

Dunn took a tumble from a horse at Sandown on Wednesday but was quickly cleared to ride in Brisbane.

"It was one of those things at the start when the horse stumbled and I came off. But I was fine and I was keen to ride at Doomben," Dunn said.

"It is my first time riding in Brisbane and to have a winner and a nose second (on Rock On Ivy) has been great."

Dunn, 20, the son of champion jockey Dwayne Dunn, is the reigning premier apprentice in Melbourne.

Another young gun, Perth's Brad Parnham, made the most of his one ride in the State of Origin jockeys series to lift Western Australia into contention.

Parnham produced a heady ride to win on Sir Donald ($5.50) in the first heat, the Class 3 Plate (1050m), and pick up 10 points .

Sir Donald can be tricky at the start but Parnham was able to get him to jump quickly and the gave him the run of the race.

"I am happy to ride in this series because I am keen to get a higher profile in the east. To win one of the heats is a great boost," he said.

Parnham's younger brother Chris, who has been riding in Victoria, had two rides and scored two points to lift WA to 17 points.

Damian Browne and Larry Cassidy failed to ride a winner for New Zealand but gained 13 points for minor placings to be in second place behind NSW.

Points after two rounds: NSW (33), New Zealand (22), South Australia (17), Western Australia (17) Queensland (13) and Victoria (8).

The third and final round is at the Gold Coast on January 7.