No New Zealand-trained horse had won Melbourne's autumn three-year-old feature since its inception in 1986, but the outstanding daughter of Proisir rose to the occasion with an unforgettable performance.

In her first start since losing her unbeaten record with a luckless fourth in the Karaka Million 3YO Classic (1600m) at Pukekohe on January 21, Legarto was eased back in the early stages of the race by Melbourne-based Kiwi jockey Michael Dee.

She was travelling beautifully coming up to the home turn, but when the time came to make her move, Dee found a wall of horses everywhere he went.

Legarto  was stopped in her tracks more than once during a rough run down the straight that saw both Holymanz and Maximillius fall heavily towards the inside of the track, but she finally saw daylight in the final 100 metres and went into overdrive.

With an astonishing late burst, she sailed past more than half a dozen rivals to score a win for the ages.

"I thought I was behind a horse that would take me through and keep me out of trouble, but I ended up left in a pocket there for quite some time," Dee said.

"To Legarto's credit, wow – she's got a very, very good turn of foot. To get out when she did and finish over the top of them was an amazing effort.

"She's still on the way up, that's for sure. She's only lightly raced and should arguably be unbeaten. I think she can come back in the spring and could be anything."

Legarto's Guineas triumph was the first Group One win in Australia for Matamata trainers Ken and Bev Kelso, who have only half a dozen horses in work.

"It's huge," Ken Kelso said. "I've said that we wouldn't retire until we got a Group One in Australia. We've only ever brought Group One horses over here, and we've had three seconds, so it's massive to win one. I just can't believe it."

Legarto has now had seven starts for six wins, earning more than $1 million in stakes for an ownership syndicate that includes Ancroft Stud principal Phillip Brown and former Waikato Racing Club chief executive Tony Enting. She was a $90,000 purchase by Ancroft Stud from Highline Thoroughbreds' draft at Karaka 2021.

"She's just an amazing filly," Kelso said. "Probably 100 metres out, we thought we were going to run fifth, sixth, seventh or eighth if we were lucky. But she does things that other horses can't do. She's pretty special.

"I think we'll take her home now. She's had a big season with two trips away – going to Christchurch for the 1000 Guineas (1600m) in the spring and then coming here. We have to chat to the owners, but as far as we're concerned, we think she should probably have a bit of a break. Then we can think about coming back in the spring, and we can dream about things like Cox Plates and Caulfield Cups."