Matthew Allen took his chance on Girl In Flight last start, creating the opportunity to realise a dream 20 years in the making.

Allen rides the Robbie Griffiths-trained filly in Saturday's Australasian Oaks at Morphettville as both jockey and trainer aim for their first Group One win.

Ryan Maloney had ridden Girl In Flight in all her starts but a scheduling clash with the stayer Sertorius in the Chairman's Handicap in Sydney forced him to give up the ride on the filly in an 1800m Group Three in Adelaide last Saturday week.

Allen won on Girl In Flight and has retained the ride in the Oaks in which the filly is favourite in early betting.

"It was a bit of luck I had there, the way it worked out," Allen said.

"It's just unfortunate for him (Maloney) that I won on her and got to keep the ride."

Allen, who does plenty of riding for the Griffiths stable, is convinced Girl In Flight is capable of landing him a first major win.

"I've been placed (in a Group One) but never won one," the 39-year-old said.

"I've been waiting a long time. It's been 20-odd years in the game.

"This would be my best chance. Count Ricardo would've been my other best chance."

Allen rode Count Ricardo to third behind West Australian stayer Plastered in the 2004 Victoria Derby.

Girl In Flight won her first three starts before stepping up to stakes company this campaign.

Her three autumn starts in Melbourne netted a first-up third in The Vanity, a fourth in the Kewney Stakes and third in the Alexandra Stakes before her Group Three Schweppes Stakes win in Adelaide.

Allen and Griffiths both labelled the last-start one-length victory terrific, and the trainer was thrilled Girl In Flight confirmed her Oaks credentials that day.

"It was her time to put the hoof up and be counted, and she did that," he said.

Last year's Thousand Guineas and Wakeful Stakes runner-up May's Dream, who finished third to Girl In Flight last start, is the second favourite.