Gai Waterhouse and Blake Shinn combined to win the Grafton Cup with Bonfire and the pair could be set for further success when they team up in two races at Randwick.

Shinn, who was once a retained rider for Tulloch Lodge, will partner last-start winner Kimberley Star for Waterhouse in the two-year-old race on Saturday.

The filly is second favourite behind Godolphin youngster Stalwart who backs up from a third at Rosehill last weekend.

Shinn and Waterhouse will also team up with Mardi who has scored a barrier trial win since she finished midfield first-up on a wet track last month.

Shinn, who has five rides at Randwick, has ridden 86-1/2 winners this season to put himself in contention for the Sydney jockeys' title.

In a three-way battle, he needs two winners at Randwick to overtake premiership leader James McDonald but will also need to stave off the challenge of Hugh Bowman.

A double at Canterbury on Wednesday moved Bowman to within half a win of Shinn and the top jockey has a strong book of six mounts at Randwick.