A victory at Flemington on VRC Oaks day might have saved Petrology from the unkindest cut of all.

Trainer David Hayes believes the horse can develop into a classy galloper if he's gelded, but after he became a stakeswinner on Thursday connections might vote to keep him intact.

Ridden by Dwayne Dunn, Petrology was backed from $10 to $8.50 and scored by a head from Chill Party ($18) with Tashbeeh ($11) a length away third.

Hayes said Petrology's performance in the Sandown Guineas (1600m) on November 15 may determine the fate of his manhood.

"As a gelding, I think he could develop into a proper horse but being a stakeswinner might complicate things," Hayes said.

"We'll look at the Sandown Guineas.

"He's just starting to get on top of his game and that will probably be the ball decider.

"We've got to see what he's worth as a stallion and what he's worth as a racehorse and I think he's worth more as a racehorse."

Hayes said he had some concerns prior to the race as Petrology was exhibiting `colty behaviour' but knew if the horse brought his A-game to the races he would still be hard to beat.

He also praised the ride of Dunn who gave the horse a lovely run and got him clear at the right time.

Dunn said Petrology appreciated the rise to 1800m and admitted the colt's finishing sprint surprised him.

"When I went full throttle he sprinted really hard," Dunn said.

"I got there a little early, but it's probably the distance that he's looking for now."