Chasing a second Derby victory, Purton concedes he faces a daunting task to succeed on the front-running galloper, while California Spangle's trainer Tony Cruz remains committed to vying for the lead with the Hong Kong Classic Cup (1800m) winner.
“I don't think 10 is a great barrier for us at all. Unfortunately, we have a number of speed runners drawn inside us who are no doubt going to try and hold their positions,” Purton said.
“In the Derby everyone gets a little bit of a rush of blood and they are probably a little bit more positive early than maybe they would be otherwise. But our horse has got an established racing pattern, so we have to use his speed and hopefully we can get across without making too much use of him.
“I have just got to hope that the other riders ride their horses sensibly to give their horses a chance to win the race. My horse is not a sit and sprint type horse, he likes to get into his rhythm and roll along.
“If he can pull it off it's going to be a monumental performance.”
Mindful of the short run from the 2000m to the turn out of the straight, Purton said: “From the 2000m start I've really got to be aggressive and press him out of the gate to clear the runners on my inside and I expect a couple of those runners to try and kick up and make it hard for me.
“When you're on a horse that's suspect at the distance, that could bring us undone. If I fire him out of the gate from 10 at this start to get across maybe it gives him that signal it's time to go and he might see that corner and think he's in a 1200m race. It could go horribly bad for us, it's a horrible draw for us – but it is what it is.”
Bidding for his seventh Hong Kong Derby success as either a trainer or jockey, Cruz said: “I think he's got that early speed and I think he's sure to go to the front and lead the race again.
“There are no other horses that have got the speed to take him on or are faster than him. I think he'll do the same thing as he's been doing all this time – go to the front, lead the race and try and dictate it.”
Romantic Warrior will jump from gate eight for Karis Teetan and the Mauritian is upbeat over the Hong Kong International Sale graduate's chances after covering ground when fourth behind California Spangle in the Hong Kong Classic Cup last month.
“Of course, I did not have any luck getting in – I thought at one stage I was going to be able to get him in three deep with some cover but with so many horses digging in on my inside, it kept me out,” Teetan said.
“I am confident he will get the trip. Of course, last time he did cover a lot of ground, he was the widest horse for the whole race and he still finished off nicely so this time we are in the middle of the track – drawn eight – so if we can get a good jump and get him in a decent position, I think he should run the distance no problem and I think he will show us his nice turn of foot this time.”
Armed with Senor Toba and Rocket Spade as he chases successive Derby triumphs after last season's success with Sky Darci, Caspar Fownes was delighted after Senor Toba landed in barrier three – the most successful since gate since 2000 with four victories, two seconds and two thirds.
“We'll always take the stats if they're in our favour and if they're not in our favour we'll try to change them,” Fownes said. “The horse is going to have the blinkers on for the first time, we took him to the gates this morning, he's starting to know how to jump better and know what we want of him.
“We want to be able to get him in some sort of position to take advantage of the gate and I think we're going to be able to do that on Sunday.”
Rocket Spade will depart from gate five under Vincent Ho, while Turin Redsun (six) and Ima Single Man (seven) will also start from the middle of the line.