Three-year-old filly Causeway Girl will be tested in town for the first time when she heads to Moonee Valley for an early season race against her own age and sex.

The Clinton McDonald-trained Causeway Girl made an impression on debut at Murtoa in country Victoria on July 16, winning an 1100m-maiden by 7-1/2-lengths.

McDonald knows the filly faces a stiffer challenge in Saturday's SAJ Fruits Handicap (1000m) on the opening weekend of the 2018/19 season but the trainer is keen to see how she measures up to get a guide on her spring prospects.

"It was a good, strong win on debut but obviously it was in a lot weaker grade so it is a big step up on Saturday," McDonald said.

"But she's a three-year-old filly and she's in good order. She's drawn a good gate and has got a good jockey on so she should run well."

Damien Oliver will ride Causeway Girl who has barrier two in the field of 14.

Stakes winner Ennis Hill, who started second favourite when unplaced in the Group One Blue Diamond Stakes earlier this year, headlines the field which includes seven last-start winners.

McDonald said Causeway Girl had always shown ability but needed a bit of time before making her debut late in her two-year-old season.

"She's in a really good spot and she worked well on Tuesday," he said.

"We understand it's a big step up in grade but you've got to give them the chance and see where they can go for you.

"This will either be a tick or a cross, and it's up to her to prove herself.

"We think she's good. It's OK to think that, but we're hoping she can prove us right."

McDonald said he liked the way Causeway Girl was able to absorb pressure on debut before kicking away in the straight.

"She was able to be eye-balled and then really give a good kick and put them to the sword," he said.

"I'm happy with that and hopefully she can do the same on Saturday."