Katelyn Mallyon's first ride for prominent trainer Mick Price has resulted in a birthday win for the apprentice at Sandown on Wednesday.

Mallyon had never ridden for Price before Wednesday's Superior Food Service Handicap (1000m) but would have made a good impression as she guided Vicario to a fast-finishing win.

The victory came on Mallyon's 19th birthday.

"That's my first ride for Mick," Mallyon said after Vicario scored by a long-neck.

"It's good for Mick to give me the opportunity and it's great to ride a winner for him."

Mallyon had planned to be in the box-seat on the three-year-old who was resuming from a spell but when the filly came out of the barriers on the back foot the apprentice was happy to let her relax near the back of the field.

"She let down really well," Mallyon said.

"And there's a lot more improvement in her."

Mallyon won last season's Melbourne apprentices' title but spent eight months on the sidelines after suffering a spinal injury in a fall at Flemington last May.

While Mallyon was successful in her first ride for Price, popular jockey Chris Symons opened the day with a winner on import Multilateral in his first ride for premier Sydney trainer Chris Waller.

Multilateral's impressive two-length win over Heyday in his second Australian start in the Slickpix Plate (1800m) was followed up by another smart performance from two-year-old Long John from the Peter Snowden stable, who earned a shot at stakes grade with his all-the-way victory in the TMB Printing Handicap (1300m).

The gelding will head to the Listed Anzac Day Stakes (1400m) at Flemington before the Darley team looks to the spring with the son of Street Cry.

"He'll come back for the longer and better races during the spring," assistant trainer Paul Snowden said.

Long John was the first leg in a double for Snowden which was brought up by three-year-old Generalife who defeated older horses in the Sportingbet Handicap (1300m).