The win was a memorable one for jockey Billy Egan landing his first major on the back of a superb ride on one of the Australia's bright staying prospects.

"I've been a battler for a few years,'' Egan said.

"I've run second in a few of them, so it's good to get the monkey off the back,'' he said.

The heavily backed Promises Kept looked to have the Derby in his keeping when he fought off the challengers on the home turn and kicked clear.

But the fighting tiger in Dunkel worked his way through horses before charging over the top of rivals and grab a brilliant Derby win.

Egan said he was confident early before the pair found themselves well back in the run.

"When we left the straight the first time I thought "this is going to be easy" I was fifth one off and then we got shuffled back,'' Egan said.

"We had work our way through them.

"He's got that killer instinct, every horse out there he wants to pass,'' he said.

Egan said we they worked into the clear he still wasn't sure they had enough time to reel in the leader.

"The further we got in the straight the harder my bloke tried,'' Egan said.

"When he sees a horse in front, he wants to pass it,'' he said.

Promises Kept was brave in defeat while Aberfeldie Boy worked home to run third, his second Group 1 placing after finishing third in last year's Victoria Derby at Flemington.