Two year-old colt Zousain had shown nice ability in two barrier trials last month but was sent to the post at $7 in a highly competitive two year-old maiden at Randwick on Wednesday.
Ridden patiently by Kerrin McEvoy he was allowed to find his feet in the early stages and then powered home up the fence taking a narrow split between runners to score an eye-catching win in the 1000 metre scamper.
Zousain held a neck advantage over a pair of Godolphin Exceed and Excel youngsters in Pindus and Hiemal.
"He is a most promising colt," said Waller, who confessed to being a bit emotional after the win.
"I'm proud of him. I know I'm not his father, but I feel like his father!
"He has so many of the attributes of his sire Zoustar, if you look at a photo of this horse and him, they are so alike.
"We were confident coming here today, he's done everything right so far."
Zousain was a $400,000 Magic Millions purchase from the Edinglassie Stud draft for David Redvers/ Mulcaster Bloodstock and runs for Qatar Bloodstock and a large group of Waller stable clients including Richard Pegum, who bred the colt.
He is the first winner for Pasar Silbano (IRE), a stakes-winning sprinter in Ireland and also a Group III winner in North America.
Edinglassie Stud will offer the current yearling from Pasar Silbano, a filly by Wandjina at Inglis Easter as Lot 281.
Zousain is the second winner for Widden Stud and Woodside Park's Zoustar joining his brilliant stakes-winning daughter Sunlight.
Zoustar has six entries for the Inglis Classic Yearling Sale starting Saturday night.