Oaks Day plans for the Leon Corstens-trained So Bella Arella might be a little premature but he will get a better idea of her ability after Friday night's Group Two Fillies Classic at Moonee Valley.

The three-year-old has been nominated for the Group One VRC Oaks during the Melbourne Cup Carnival but Corstens has his doubts whether she can see out the 2500 metres at this stage of her career.

The lightly-raced Choisir filly notched her maiden victory over 1400m at Cranbourne earlier in the month.

"I'm very pleased with her and I think she is going extra well," said Corstens.

"The 1400 metre win was quite nice and I'd be disappointed if she can't get the 1600 metres on Friday.

"But I don't know about the Oaks. I don't know if she can get the journey."

There are only eight fillies entered for the $200,000 Fillies Classic including the David Hayes-trained Group Two winner Gregers, third in last week's Group One Thousand Guineas.

"It's not an easy field but I don't think there is a hell of a lot between the fillies," Corstens said.

"We'll keep plugging along and see what eventuates."

Another of Corstens' fillies running on Friday night is Judicial Rock who tackles the Listed Chandler Macleod Crockett Stakes (1200m).

The three-year-old filly has had only five starts and scored her only win in an 1100m maiden at Wodonga on September 2.

"I'm very pleased with her and I think she is going extra well," said Corstens.

"Hopefully she will stand up and be counted."