The Cox Plate is on the table for Godolphin colt Sweynesse after he maintained his unbeaten record in Saturday's Group Three Gloaming Stakes at Rosehill.

In a week when Kerrin McEvoy announced he would relinquish his job as retained rider for Sheikh Mohammed, he proved the combination would still be a force on Australian racetracks with a Gloaming Stakes ride praised by trainer John O'Shea.

"The horse was beautifully navigated by Kerrin," O'Shea said.

"Kerrin has ridden for us before, he's riding for us today and he'll ride for us in the future. As far as I'm concerned nothing's changed."

McEvoy will be replaced by Blake Shinn when Sweynesse races next in the Spring Champion Stakes at Randwick due to McEvoy's pre-standing riding commitments in Melbourne.

He has been booked to partner Rubick in the Schillaci Stakes and will also ride Kumaon or Ghibellines for Godolphin in the Caulfield Guineas.

The door has been left open for McEvoy to reunite with Sweynesse in the Cox Plate where the three-year-old would carry 49.5kg.

"That hasn't been spoken about yet but that's an option as well. I've done the weight before twice with Helmet and Long John," McEvoy said.

Sweynesse started a $2.40 equal favourite and after settling last of the six runners produced a sharp turn of foot to claim the other fancy Diamond Valores and score by a length.

He is emerging as the horse that could be the cornerstone of O'Shea's tenure with Godolphin as the trainer revealed his Cox Plate ambitions.

"The machinations of the Cox Plate are a bit different this year and he's a horse with genuine staying ability and with form lines that have traditionally been effective," O'Shea said.

"It's an option for us. Obviously we've got to get him home and make sure he pulls up well.

"If he pulls up well he'll go to the Spring Champion and then we'll go from there."