Long-shot debut winner Astro Castro has given trainer Alan Hunter his first winner at Flemington.

Astro Castro was sent to the barrier as a $101 outsider in Saturday's VRC Recognition Handicap.

Ridden by Jason Benbow, Astro Castro defeated Tyrannize ($9) by a half-neck, with Badajoz ($4.80) 1-1/2 lengths away at third.

Hunter, who prepares a small team at Geelong, has been training for seven years and was confident that Astro Castro had ability.

But he was shocked by the win, admitting he did not have "a cent" on the gelding at the cricket-score odds.

"It was a throw at the stumps," Hunter said.

"We thought he was smart but it's only his second preparation.

"He came to me in the middle of last year and we took him to Ballarat for a 900-metre jump-out to give him a day out from Geelong in early June, which he won in the last stride.

"Anthony Boyd rode him and said he was a pretty smart horse.

"I'm not putting the race down but the highest rater was a 75 and we thought we would have a crack in town before he turned four."

Astro Castro races in the colours of Hunter's grandfather Curly Burns, a successful trainer in country Victoria.

"These colours ran second in an Australian Cup, they've been in a Melbourne Cup, a Victoria Derby and placed in a South Australian Derby," he said.