Champion trainer Caspar Fownes says preparing Military Attack for Sunday's Group One Audemars Piguet QE II Cup has been one of the greatest challenges of his career.

The former horse of the year has battled a range of setbacks in the lead-up to the HK$20 million feature at Sha Tin.

"It's been tough and if it is not one thing, it's been another," said Fownes, whose seven-year-old gelding was to face a regulation race-eve check on Saturday morning.

"It can be so frustrating sometimes. Just when you think you have him right, something else comes up."

Sore feet, chronic joint pain and weight loss due to a lack of appetite have been just some of Military Attack's issues that have had Fownes working overtime since a narrow second to Designs On Rome in the Hong Kong Cup four and-a-half months ago.

"And even that preparation wasn't straightforward," he said.

The three-time Group One winner was scratched from what would have been his first-up run in the Group Three Centenary Vase in early February before finishing fourth behind Designs On Rome in last month's Citibank Hong Kong Gold Cup.

"It has been problem after problem. He doesn't have great feet, so that has been one of the main challenges in recent weeks, getting the right shoes on him and hardening his feet up," Fownes said.

But despite the persistent niggles, a change of season has Military Attack's coat blooming. Fownes said the horse's body weight was "spot on" ahead of a race Military Attack won two years ago during his breakout season.

"In that way, his appearance, fitness and condition, I have him right where I want him. He looks fantastic, and his trial last week was very encouraging," Fownes said.

"His last gallop on Wednesday was great, and he is eating well and he, obviously, likes this time of year. He will have his work cut out against the big boys; Designs On Rome again looks hard to beat, and so does David Hayes' horse, Criterion."

In Military Attack's favour is barrier two, from where Fownes said he would be instructing jockey Zac Purton to take a handy position on his tactically versatile charge, who will wear blinkers for the second time on Sunday.

"He'll go forward, taking advantage of the gate," he said.

"The blinkers stay on, as Zac feels the horse has been distracted by the extra signage they have inside of the track on the big days. That might have cost him a race, so for a race like this we don't want to leave anything to chance."

Fownes also revealed that his other stable star Lucky Nine would take his place in the Group Two Sprint Cup after initially considering withdrawing the eight-year-old with a view to next month's KrisFlyer International Sprint in Singapore.

Lucky Nine will be chasing three straight wins at Kranji and Fownes hopes Sunday's run will bring him back to his best.

"His coat isn't 100 per cent, but this race will bring it on - he is 80 per cent right," the trainer said. "He has worked well and scoped clean a few times now, so we are happy with him."