The fortunes of two sought-after stallion prospects have swung on the result of a protest hearing at Flemington.

The Darren Weir-trained Palentino was first past the post in the Group Three CS Hayes Stakes ahead of the Mike Moroney-trained Tivaci.

Craig Williams lodged a protest after being pushed wide at the 900m on Tivaci in Saturday's race when Mark Zahra came out abruptly on Palentino.

Williams claimed the interference cost his mount up to two lengths, much more than the shorthead that separated the pair at the finish.

Racing Victoria chief steward Terry Bailey said Tivaci went from racing three wide to being out six wide.

"We believe the interference exceeds the winning margin and without the interference Tivaci would have won the race," Bailey said.

Moroney said the decision to uphold the protest was a massive decision as it provided Tivaci with all-important black type as a future stallion.

Tivaci and stablemate, third-placed Tulsa, are likely to head towards the Australian Guineas on March 5 but Moroney could split the pair with one heading to the Randwick Guineas in Sydney on the same day.

"Tulsa probably should have won the race if he had gone straight but laid back in behind Tivaci," Moroney said.

"The problem is neither of them have been right-handed and both are unknown in my opinion.

"We may run them both here but we'll just see."

Weir said Palentino would head to the Australian Guineas where he would be joined by stablemates Mahuta and Perfect Reflection.