On a day when Sydney's glamour two-year-olds staked their claims for the Blue Diamond Stakes at Caulfield, Law was at home at Randwick taking the next step to the Golden Slipper.

Earthquake and Rubick won their respective Preludes in Melbourne ahead of the $1 million Group One race in two weeks.

The winner of the Breeders' Plate, Law ($1.65) only had to front up against three rivals on his home track and took care of business with a 3-1/4 length win over Hostwin Pegasus.

His prize money added to his Breeders Plate stakes gives trainer Gai Waterhouse some leeway heading to the $3.5 million Slipper in April.

"It's onwards and upwards from here," Waterhouse said.

"Once he balanced up it was a matter of how far.

"We'll sit down and talk about where we go from here on the way to the Slipper."

The colt, who is from the first crop of Lonhro stallion Denman, had to do a bit of work early to stay in touch with Hostwin Pegasus ($7) and Klammer ($4.60).

But once he balanced up in the straight, Law strode to the lead and went to the line strongly.

"He had to do it at both ends," jockey Nash Rawiller said.

"He wanted to get on with the job early but he was strong at the finish."

Law is raced by a syndicate put together by Denise Martin's Star Thoroughbreds whose colours were carried to Slipper glory by Sebring in 2008.

"Golden Slipper here we come," Martin said.