Class filly Lumosty has defied a betting drift to record an explosive first-up victory at Flemington.

The Robert Smerdon-trained daughter of Fastnet Rock drifted from $3.20 to $5 in the All Victorian Sprint Series Heat 2 before winning in 1min02.4secs, just 0.25secs outside the 1100m track record.

Stable foreman Stuart Webb said the team was confident of success at Lumosty's return run after finishing sixth in the VRC Oaks.

He said he was surprised by the alarming betting drift.

"I had a couple of text messages before the race asking if she had lost a leg or something," Webb said.

"She ran great time and hopefully she can go onwards from here."

Webb said the stable has known for a long time that she was a filly well above average.

He wouldn't be drawn on an immediate program for the filly but said the stable was aiming towards next month's Group One Tattersall's Tiara at the Gold Coast.

He said Lumosty was clean-winded and would hopefully get to Brisbane and continue on with what she showed on Saturday.

"Where she'll run next I'm not sure but Robert will digest what happened today and make that decision," Webb said.

Winning jockey Chris Parnham, who earlier in the day landed his first Flemington winner, was impressed with the acceleration the filly showed after being held up for a run.

He's convinced the three-year-old is up to Group One company.

"There was a bit of interference up the straight but she showed she's better than that group," he said.

"She gives me the feel that she is up to that Group One company."

Runner-up Pago Rock had support from $16 to $13 before finishing a three-length second with Hard Romp, backed from $6 to $5, a half-neck away third.

Reparations was backed from $6 into to $4.40 favouritism before finishing fourth.