It was a war Godolphin's jockey James McDonald thought might have been over before it started.

The minutes before the start of The BMW, which Godolphin won with Hartnell, were more tense than the race itself for McDonald.

"He was just full of himself and [when he] got up in the stalls [he] got his leg on the gates," McDonald said. "I was worried, real worried. Once I got back on him after the vet had a look at him, he was just ready to go.

"I thought my race was over a couple of other times but he is a super horse and To The World isn't bad either."

It was a win heard around the world with Sheikh Mohammed and his bloodstock advisor John Ferguson watching from Dubai. They were straight on the phone to trainer John O'Shea.

"John just said 'we were happy we have just won a big race on Dubai World Cup day'," O'Shea said.

"That was so exciting. To see two horses go at each other from that far out and to come out on top of a world-class horse [in To The World] is amazing."

Hartnell had a 1 length margin on To The World at the line with outsider Beaten Up a half neck back in third.  It was part of four winners for the afternoon for Godolphin, while McDonald added another to have a personal tally of five.

Those numbers read well but The BMW outshone anything seen in Australian racing for the past couple of years. It was racing at its best.

With champion horses at each other from a long way out, it was a 2 minute battle that would be remembered.

McDonald matched minds with  To The World's jockey Nick Hall but won the chess game and then had the superior horse at the end of 2400metres.

The pair travelled midfield together and were ready to launch their claims at the 800m mark but as they pushed forward Opinion looked to go amiss in front of them.

"I thought my race was over again there but he just got back into his rhythm so quickly," McDonald said. "He is a super stayer and kept going. This is the stuff of dreams."

By the turn, Hartnell and To The World had hit the front and it was down to  survival of the fittest.

"He just outstayed me," Hall said said to his connections. "He will be better for that run."

To The World is a serious horse, the best three-year-old from Japan last year, and brought his A-grade  game. Hartnell, a Royal Ascot winner last year, has both a new lease of life in Australia.

"Doing the form, we looked to have two very special horses here today and, when they cleared out, wasn't it exciting," O'Shea said.

"He's a lovely horse. He's beat a world-class horse today.

"To be fair, the Japanese horse looked to me to have plenty of improvement but we'll take the victory."