Walker is expecting the Flemington track to suit Truth Or Dare on Saturday.
"I think the big track will suit him," Walker said.
"His win was good because he jumped from 1200 (metres) to a mile and being on the tighter track (at Cranbourne) it took him a while to get wound up.
"But it was a good win, and obviously it's a step up on Saturday, but he should like Flemington." - Mark Walker
Walker said the Derby had been in the back of his mind when Truth Or Dare started his campaign, and the team took a punt on sending the gelding to his Cranbourne stables.
It paid a dividend straight away with the first-up Cranbourne win.
"We took a bit of a punt to bring him over here after his first-up run, but it was so wet at home," Walker said.
"Luckily, he's gone the right way, and he worked well on Tuesday with Michael Dee on and then he spent some time down at the beach.
"Hopefully he's up to it."