While the Pierro Plate does not yet carry Black Type, it was easily the standard of a Black Type race and provided Santos (images Steve Hart) with a real opportunity to show his class.
Tuned up with two recent trial wins, he stalked the leader and proved way too strong in the run to the line winning the 1100 metre dash by two and a half lengths with Tim Clark in the saddle.
"I was pretty confident when he sat outside the leader, the further he went the stronger he got," said Tim Clark.
"He's put up his hand to be in contention for the big races."
It was the first win for Santos, who was third in the Listed ATC Breeders Plate on debut in the spring and then fourth at Randwick to Legend of Condor, who faded to fourth in this assignment.
"This has been our Golden Slipper horse from day one, but he was still very immature in the spring," revealed Gai Waterhouse.
"He's furnished into a beautiful colt now.
"He'll have another run before the Slipper, but today was a crucial race for us and he's won it."
Santos was a $180,000 Inglis Classic purchase for his trainers from the Emirates Park draft and is a half-brother to Japanese Group III winner Melagrana from the good producer Ghaliah, a half-sister to Group winners Mutawaajid, Adeewin and Fatoon, the dam of Group I winner Fat Al.
He is the second last foal from Ghaliah, who died in 2016 and her last foal is a filly by Smart Missile.