Prepared by Team Hawkes, Overshare (pictured Darryl Sherer) resumed from a spell with a good fourth to Menari in the Listed ATC Rosebud at the start of the month and proved the strength of that form with a dashing victory.
He led throughout for Dwayne Dunn and kicked on strongly to win the 1200 metre sprint by a length.
Co-trainer Wayne Hawkes said mental maturity has been the key to Overshare realising his potential.
"The difference between this time and the last time he was here was he wanted to get a bit keen," co-trainer Wayne Hawkes said.
"That was young nerves but today he was a lot quieter in the gates and Dwayne (Dunn) gave him a peach of the ride.
"It's great for Spendthrift because he's now a stakes winner. He's another colt that will go off to stud and that's what it's all about for them."
Overshare was tried in the Blue Diamond Prelude and Blue Diamond Preview last season and Dunn said a lot of work had gone into getting Overshare to relax.
"In his last couple of runs down here he overdid it against some good horses," Dunn said.
"It was against him at the end because he would over do it but today there was moderate tempo and he kicked well off the corner."
A $320,000 Inglis Easter purchase from the Victoria Park draft for Spendthrift Australia, Overshare has two wins from five starts and prizemoney topping $123,000.
He is the first winner for Group III placed Redoute's Choice mare Savannah's Choice, who boasts an impressive international pedigree.
Savannah's Choice is a half-sister to Champion Japanese 3YO Filly Cesario, the dam of Japan Cup winner Epiphania and the 2015 Champion 2YO Japanese Colt Leontes.
Savannah's Choice has already foaled this spring producing a colt by More Than Ready (USA).
Overshare is the 22nd stakes-winner for Yarraman Park's flagship sire I Am Invincible, who sired six winners on Saturday!
Overshare is the 22nd stakes-winner for Yarraman Park's flagship sire I Am Invincible, who sired six winners on Saturday!