Toulouse will attempt to follow stablemate Ace High's path to the Group One Australian Derby next autumn after breaking his maiden at Rosehill.
The two-year-old has responded positively to his recent gelding, with trainer David Payne nailing the quinella in the Australian Turf Club Handicap (1400m) on Saturday.
Toulouse ($4.40) hit the line 1-1/2 lengths clear of Silent Explorer ($12) to record his first win at the fourth attempt.
Payne was pleased with the duo, who were sired by Lope de Vega, a stallion who also provided the South African with success through Be Like Dad and French Fern.
"I think (Toulouse) could be a derby horse. The further he goes, the better," Payne said.
He said Toulouse had improved significantly since health concerns were resolved.
"He had a lot of blood issues and every time I ran him (last preparation) he didn't go into those races a hundred per cent," he said.
"When we put him away, we gelded him and he's come back a different horse, and he'll improve a couple of lengths on this run."
Jockey Jason Collett also noticed a change in Toulouse's demeanour since he rode him in the Pierro Plate in February.
"He's a lovely horse, actually. I rode him last prep during the start of the autumn and it was all happening too soon for him," he said.
"David gave him more time to develop and gelding him has probably helped him."
Ronstar, the $2.40 favourite, was third 1-1/2 lengths further back.