Gai Waterhouse may be the reigning monarch of Sydney's rich Doncaster Mile but trainer Chris Waller has proved himself a serious contender to the throne.

One-time battler trainer Waller notched up his fifth Doncaster Mile win at Randwick on Monday, with Kermadec taking the trophy in the highlight of the rain-delayed Championships racing carnival.

After the opening day of The Championships, Sydney's richest racing carnival, was postponed by heavy rain on Saturday Waller had already suffered through an extended wait.

And as Kermadec - among the favourites for the $3 million headline race - was not an initial qualifier, Waller needed two other horses scratched before the three-year-old was in.

News came through at 7.30am on Monday.

"We had to wait to the death to get him in the field," a tearful Waller said after the race.

The Doncaster win brings Waller closer to Waterhouse's seven Doncaster wins. Waterhouse's favourite for the Doncaster, Pornichet, finished fifth on a day when the superstar trainer failed to record a win.

"If you're making headway on Gai you're doing pretty well," Waller said.

Randwick was left a rain-soaked ghost-town on Saturday after chief steward Ray Murrihy cancelled the meeting with concerns about jockey and horse safety in the wet conditions and low visibility.

Just over 11,500 people filed into Randwick on Easter Monday, the number was well down on the target of 25,000 expected through the gate on Saturday.

But with some of the richest races in NSW on the card and nearly $10 million in prizemoney up for grabs, punters were repaid for their dedication.

Before Glen Boss piloted Kermadec to a win, crowd favourite jockey Tommy Berry steered sprinter Chautauqua from the back of pack to win by a nose in the $2.5 million, 1200m Darley TJ Smith Stakes.

"I've never pulled up so quickly to come back and have a look at the photo," Berry said after the race.

The Championships, billed as Sydney's answer to the Melbourne Cup, had some of their glamour washed off by Saturday's rain with flagship events such as the exclusive, $450-a-head Little Sydney restaurant precinct, and Myer's Fashions on the Field competition, cancelled for Monday.

Both events will be back on Saturday, however, for the second day of the Championships which features the $4 million Queen Elizabeth Stakes, the world's richest turf race over 2000m.