A week after a potentially serious fall, jockey Craig Williams has made a triumphant return to riding aboard Big Duke in the Chairman's Handicap at Randwick.

Williams suffered concussion when he came off The Gold Trail past the post in last Saturday's Mornington Cup, when the English Godolphin horse fatally broke down.

The jockey passed a cognitive test on Friday and expressed his gratitude to trainer Darren Weir and the Australian Bloodstock syndicate for keeping the ride open on the Sydney Cup favourite in the 2600-race.

"It's been overwhelming with the support I've had from people in racing, fellow jockeys as well as family and friends," Williams said.

"I'm very grateful to Darren Weir and the owners for honouring their commitment. A lot of things changed on Sunday with whether or not I could ride.

"It's obviously fantastic to get a win on one of the great days of the Australian Racing Calendar, Day One of The Championships at Randwick."

Big Duke gave premier Melbourne trainer Weir his first Sydney win in the Manion Cup two weeks ago and backed up on Saturday as the $2.45 favourite to beat Aloft ($4.40) by two lengths.

Jamie Lovett of Australian Bloodstock was more than happy with Williams' ride.

"It was a terrific ride taking runs," Lovett said.

"I thought he really let down with the big weight."

Big Duke carried 58kg on Saturday but drops to 51.5kg for the Cup (3200m) next week, for which he is the $2.80 favourite.

Godolphin's visiting team suffered another blow when Polarisation was scratched from the Chairman's with a swollen hock and he faces a task to make the field for the Sydney Cup.