Godolphin's Thunder Snow has become the first dual winner of the Dubai World Cup in a fighting finish to the Meydan showpiece.

The five-year-old gave trainer Saeed bin Suroor a record eighth World Cup success last season, dominating proceedings from the front in the hands of Belgian superstar jockey Christophe Soumillon.

With Soumillon again in the saddle on Saturday (Sunday AEDT), Thunder Snow was settled on the heels of the leaders and tracked the strong-travelling North America and Gronkowski into the home straight.

As North America dropped away, it turned into a straight shootout between Thunder Snow and Gronkowski and while the latter did not go down without a fight, Thunder Snow claimed an historic victory by the narrowest of margins.

"Last year I went to the lead and won by five or six lengths. Today I had to fight hard as when I came to the turn, the two horses in front were going better than me," Soumillon said.

"It was very hard and I was looking more like a Cheltenham jumps jockey than an American-style (Flat) jockey in the end!

"I want to say a big thank you to Saeed bin Suroor and also Sheikh Mohammed as they gave me confidence before the race.

"And thanks to Thunder Snow because without him I would not be able to do these kinds of things."

Bin Suroor said Soumillon was a big part of Thunder Snow's success.

"The Dubai World Cup has been extremely kind to me and to have the pleasure of training a horse like Thunder Snow is something that's hard to describe," he said.

"I have always dreamed that he could win one World Cup, but to become the first horse to win two is something I am finding hard to believe.

"... Christophe needs to take a lot of the credit, as he has formed such a wonderful relationship with him.

"The two of them get on so well and from his stall on the outside (12), Christophe knew the only way he could win the race was to become competitive straight away."

Thunder Snow is by dual hemisphere stallion Helmet, a triple Group One winner in Australia.