The sister of multiple Group One winner Mentality is starting to live up to her breeding with victory at Flemington giving her two wins from three starts.

The filly raced on the pace and dug deep to beat Benny Dee by a long neck in Wednesday's racing.com Handicap (1420m).

Co-trainer Wayne Hawkes said Rationality had been allowed time to develop and would continue to improve into her four-year-old year.

After winning her maiden on the Geelong Synthetic track, Rationality progressed to city company at Flemington and the plan is now to win a stakes race with the daughter on Flying Spur.

The filly is raced by John Messara's Arrowfield Stud and broadcaster Alan Jones' Belford Productions.

"They're not in a rush with her and neither are we," Hawkes said.

"She's a big, strong filly going somewhere.

"We'll probably give her at least one more and then put her away.

"At the end of the day she's a city winner so now we've got to try and get a stakes race for her."

Hawkes said Rationality was a cracking sort of filly, a lot like her elder brother Mentality who won three Group One races over the Randwick mile - the Champagne Stakes, Randwick Guineas and George Main Stakes.

"She's Mentality's sister and she's probably the best sort I've seen since him," Hawkes said.

"We've got the two-year-old half-brother Collegiate that is also a good sort but there has been a few in between that weren't as good."