Former Adelaide trainer Jeremy Gask has fallen agonisingly short of his lifetime ambition to win the King's Stand Stakes at Royal Ascot.

England-based Gask's veteran sprinter Medicean Man looked as though he might cause a 50-1 upset in the 1000m Group One contest, but Robert Cowell's Goldream got up to beat him by a short head on the line.

Muthmir was just a neck away in third.

"I've never been happier to finish second but at the same time it is frustrating," Gask said after the race on Tuesday (Wednesday morning AEST).

"It was a bob of the heads and his head was up right at the line.

"He would have fulfilled a life ambition to win this race but we have to be pleased with that (second)."

Medicean Man in 2014 ran an excellent fourth in the King's Stand. He was 11th in 2013 and fourth in 2012.

Gask, who operates out of Wiltshire, is already planning to return next year when the sprinter will be a 10-year-old.

Before that, Medicean Man could return to Meydan in Dubai for the start of the 2016 season.

"He never really has many early season targets so we will look to go back there next year and hopefully he can come back for this race (the King's Stand) again in 12 months time," the Aussie expat said.

Gask was full of praise for Brazilian jockey Joao Moreira, who stepped in at the last minute for Damien Oliver.

Oliver was due to leave Melbourne on Sunday but his trip to Ascot was delayed when he suffered concussion and general soreness in a fall at Bendigo last Thursday.

He's since been given the all-clear to travel to England to ride Wandjina in the Diamond Jubilee Stakes on Saturday.

"Joao was a magnificent replacement and he has given the horse a great ride," Gask said.

"Not everything went to plan, as he did get exposed early on and he would have liked more cover early on, but it was still a great performance."