A man who scours the world in search of big-race winners has claimed one of the biggest races of them all with a horse born and bred in his own backyard.

Fawkner, a son of Lloyd Williams' unbeaten galloper Reset, scored one of the most convincing Caulfield Cup wins of recent times, powering away from a high-class international field in a perfect execution of an inspired plan.

In a win that continues an extraordinary 12 months of big-race wins for Williams, Fawkner added the $2.5 million race to the Melbourne Cup won last year by his imported galloper Green Moon and Mourayan's Sydney Cup of last autumn.

No Australian owner has bought more foreign horses than Williams with a figure of around 200 a popular guess. Of the 10 he originally entered for the Cup, eight were imports.

And the winner only remained in his name because a prospective purchaser didn't pay up after Williams agreed to sell Fawkner to him almost a year ago.

"After he finished second in the Emirates Stakes last year someone rang up and wanted to buy him," said Williams' son and Fawkner's part-owner Nick Williams.

"We agreed to sell him, but when the time came to pay they didn't stump up the money."

The failed sale gave Williams and his trainer Robert Hickmott the inspiration to set the horse who had rarely run beyond 1600m for the race regarded as the world's toughest 2400m handicap.

"When the sale didn't go through Dad said he was glad the bloke didn't pay," Williams said.

"He said `I've being thinking about it, we're going to win the Caulfield Cup with this horse'."

For the owner who has built a racing empire in a bid to satisfy his passion for winning Melbourne Cups - and who has won four of them - this was his first Caulfield Cup.

And the home-grown theme continued beyond the horse.

Jockey Nick Hall, whose father Greg partnered many of Williams' major winners, is the owner's godson.

He also produced a gem of a ride, finding a position one of the fence in the first 200m and then plotting a course past tiring horses over the final 500m.

Hall produced Fawkner ($11) at the 250m and the six-year-old accelerated clear of his rivals to score by 1-1/2 lengths.

The English runner Dandino ($11) made up good ground to finish second, a nose in front of Dear Demi ($26) who also came from near the tail of the field.

"He is such a special horse to me," Hall said.

"They've prepared him to the absolute second and they produced him today."

The favourite Hawkspur, who also settled among the last few, made up reasonable ground to finish seventh.