In 164 runnings of the Melbourne Cup, there have been a fair few surprise winners.

But there may not have been any upset bigger than Knight's Choice's win in the race that stops a nation.

A jockey, better known as a singer on an Australian reality show, riding an absolute outsider to victory ahead of the international raiders and star imported stayers?

For Robbie Dolan on board Knight's Choice, the biggest win of his career was a shock to everyone at Flemington — including him.

After pulling out a heart-stopping finish to beat Japanese horse Warp Speed in a photo finish, Dolan was in dreamland.

"Pinch me, I'm dreaming," he said to Channel Nine after the race.

"It is incredible. I can't believe it. I don't even know what to say."

Dolan is an accomplished rider, with the Melbourne Cup his 348th career win.

But before this race, Kildare-born Dolan was better known to most Australians for his run on The Voice, where he displayed some decent singing chops.

Asked if he could sing a song, Dolan said: "I think I'll be singing for the rest of me life after that."

Knight's Choice, trained by John Symons and trailblazing trainer Sheila Laxon, had not won in 335 days, and had its last run before the Cup when it came fifth in the Bendigo Cup.

"You can't do it without Sheila and John [Symons]," Dolan said.

"A lot of people doubted them. And to be honest, I didn't. I really liked his run at Bendigo and he hit the line well and was unlucky not to be placed."

But Laxon, who in 2001 was the first female trainer to win the Melbourne Cup when Ethereal won the Caulfield-Melbourne Cup double, had produced the horse to a tee.

And Dolan and Knight's Choice did the rest, beating Warp Speed and the Ciaron Maher-trained Okita Soushi, with Godolphin's Zardozi — trained by James Cummings — fourth.

Knight's Choice had been four lengths back at the 400-metre mark, in 10th place, as Land Legend hit the front.

But Dolan held his nerve and got the run to start motoring home.

In the finishing stages of the race, Okita Soushi — ridden by Jamie Kah — led from Zardozi on the fence, but it was Knight's Choice and Warp Speed who came through the middle.

Dolan and Knight's Choice hit the front at the 60m mark and clung on to win in a bob of the heads with Warp Speed.

Laxon told Nine her co-trainer, Symons, had always been confident despite Knight's Choice's outsider status.

"He did, he did. He started the race and he knew how to ride him. We didn't give him instructions. He knew what to do," she said.

"I love it being down for the Australians. The Australian horse has done it, and Robbie is Australian now as well, so I'm thrilled to win the Cup, and it is the people's Cup, and that's what it is all about."

Knight's Choice became only the sixth Australian-bred horse to win since 1993, and the first since Vow and Declare in 2019.

The favourites for the race, the Chris Waller-trained Buckaroo, and the Willie Mullins-trained Vauban, finished ninth and 11th.

The Gai Waterhouse-trained Just Fine had led the field for much of the race, trying to win from the front.

The seven-year-old faded in the straight to finish last, but like the rest of the field was OK after the race.