Ex-pat Australian trainer Jeremy Gask is hoping for a King's Stand upset with Medicean Man, winner of a Listed event at Haydock earlier this month.

Medicean Man is a 20-1 chance in the Group One sprint on the opening day of the Royal Ascot meeting on Tuesday (Wednesday AEST) with South African Shea Shea the 2-1 favourite.

Australian Group One winner Shamexpress is at 9-1.

Gask, who moved to England several years ago after a successful career in Adelaide, said he hoped Medicean Man could produce his best at Ascot where he has won over the 1200m course.

"I'm very happy with him and I'm happy with the draw (nine) and the track conditions," Gask said.

"He did well out in Dubai earlier in the year, but I think by the time it came round to World Cup night, he'd had enough.

"He seems in really good form at the moment and I think he deserves to take his chance.

"If Shea Shea turns up in the same form he did in Dubai, he's going to be very hard to beat, but this is Ascot, it's a different track for him, so we'll see.

"We know our horse loves it there."

Shea Shea's trainer Mike de Kock is confident his charge can as the first South African-trained Royal Ascot winner.

I actually think the uphill finish might suit him as he gets going late, but even though he broke the track record twice at Meydan, South Africa has yet to have a winner at Royal Ascot," De Kock said.

"He's happy, his coat is good, he's eating well and his work has been exceptional. I'm hoping he is in good form.

"It would be great to have the win on the CV but if you look at his form, including in South Africa, he's either won or come nowhere.

"There's no grey area in between so we hope it's another win at Ascot."