The most expensive horse in the Golden Slipper has won the world's richest race for two-year-olds to give trainer John Hawkes a fourth win and jockey Brenton Avdulla a first.

Estijaab cost $1.7 million at the 2017 Easter Sale and also proved to be the fastest, flying out of her wide barrier to cross to the front and sustain the pressure over the 1200 metres of Saturday's feature at Rosehill.

Hawkes trained Guineas (1997) and Forensics (2007) to win for Jack and Bob Ingham's Woodlands Stud and Mossfun in 2014 in his public training partnership with his sons Michael and Wayne.

Like Mossfun, Estijaab is owned by Nasser Lootah's Emirates Park Stud.

A drifter in early markets since being beaten by Sunlight in the Silver Slipper, Estijaab was at $8.50 on race day with Blue Diamond Stakes winner Written By the $4.80 favourite.

"Everybody went off her after the other day but you've got have them peaking on the right day," Hawkes said.

"It's no good having them win the Slipper two weeks before.

"Her biggest attribute is her gate speed. She has shown us a lot from day one.

"They are all different and she doesn't know how much she cost but it's good to see the expensive ones win."

Estijaab held off the fast-finishing Oohood ($17) by a long head with Sunlight ($5) another 1-1/4 lengths third for a fillies trifecta with Written By a close fourth.

The result was bittersweet for trainer Tony McEvoy, who trained the minor placegetters.

"I just wish we'd been a spot closer with Sunlight," he said.

"She tried very hard and just wasn't good enough on the day."

All the honours were with Esitjaab and Avdulla, who celebrated his first win in what is considered one of the four major races in Australia along with the Cox Plate and Caulfield and Melbourne Cups.

"It's very emotional," Avdulla said.

"I've put in a lot of hard work with the stable and they are very loyal John, Michael and Wayne."

"Ever since I've been on this girl since day dot she's given me a special feel.

"You dream of riding Golden Slipper winners. When I was 15 and starting apprentice school I was the biggest in the class and they said I had 12 months in the saddle and then I was going back to school.

"My first reaction when she drew 14 was I've got no hope, but then the more I looked at everything wanting to take a sit, I knew I could back her gate speed and ride her positive early and she could get across and control. That's what she did.

"I've just won a Slipper. I don't know what to say."

There were few hard luck stories with Written By's jockey Jordan Childs saying he raced a little fresh, and Sunlight's rider Luke Currie saying the filly ran well but could not pick up the leader.

Written By was one of five horses passed fit to race after their floats were stuck in traffic on the way from Randwick to Rosehill.