Prepared by Team Hawkes, he was a close second on debut back in June when he did plenty wrong at Rosehill, but has obviously returned a more tractable colt.
He travelled well for Brenton Avdulla and surged up three wide on the turn before racing away to win the 1300 metre maiden by four and a quarter lengths as a short priced favourite.
"What you see is what you get," Avdulla said.
"He's still pretty raw and 1300 first up was an ask, but he has plenty of ability and is with the right team."
A $1.7million Inglis Easter purchase from the Arrowfield draft for George Moore Bloodstock, Diplomatico is a half-brother to Group III winner Havana from winning Anabaa (USA) mare Top Cuban.
He was the equal highest priced Snitzel yearling sold in 2017 along with Golden Slipper winner Estijaab, who was sold from the same draft also at Inglis Easter.
Top Cuban has a yearling colt by Redoute's Choice and was covered last spring by Snitzel.
Top Cuban has a yearling colt by Redoute's Choice and was covered last spring by Snitzel.