Nash Rawiller turned his focus to a session of boxing in a bid to land a knockout blow on Royal Descent in the $3 million Doncaster Mile at Randwick on Saturday.

Regarded as a heavyweight jockey, Rawiller will ride at his lightest since the Melbourne spring carnival when he partners Royal Descent at 54kg.

"I was 55(kilograms) this morning," Rawiller said.

"I was hoping I'd be a fraction better but there's certainly no concerns at all."

Royal Descent is one of six Doncaster acceptors for trainer Chris Waller and her affinity for wet tracks has brought her right into calculations.

She posted a 10-length win on a bog track in the ATC Oaks last year and Rawiller said he was delighted with her form in two autumn runs.

Rawiller will spend part of the countdown to the start of The Championships in his local gym.

He was hoping to reward himself with a small piece of fish as his Friday evening meal but he is convinced the hardship will be worth it.

"I was very happy with the way she hit the line in the Coolmore," Rawiller said.

"This preparation she has been getting on wet tracks and feeling better for it. I'm rapt with the way she's going."

While heavy ground will help Royal Descent, a $15 to $11 betting mover on Friday, it's likely to cause the scratching of stablemate and race topweight Boban.

Boban has been unplaced in three soft-track runs, his including his most recent start in the George Ryder Stakes.

Rawiller said a wide draw provided him with his biggest obstacle on Royal Descent.

"I would have much preferred to have drawn barrier eight because I could ride her wherever I wanted to then," Rawiller said.

"I just think in these big races, you need a bit of an early break to win."

Waller and Rawiller linked to win the 2010 Doncaster with Rangirangdoo while the trainer is chasing his fourth victory in the race since a breakthrough Group One courtesy of Triple Honour in 2008.

The premier trainer also has last year's winner Sacred Falls returning but it is his French import Weary who has been the best backed.

Weary earned a place in the Doncaster field after winning at Rosehill last Saturday and the Tommy Berry ride is into $5.50 with with expectations he could press Messene ($4.60) for favouritism.