Zoustar kept his unbeaten record intact in the BRC Sires' Produce Stakes and strengthened trainer Chris Waller's grip on next month's Group One JJ Atkins.

Ridden by Jim Cassidy, Zoustar ($4.40) defeated his stablemate Vilanova ($8) to win the Sires by 1-1/4 lengths with Bound For Earth ($8.50) a long neck away third.

"They're two lovely colts and it's all looking good for two weeks time at Eagle Farm," Waller said.

"I was trying desperately to keep them apart and I thought about running Zoustar at Randwick but I changed my mind when it became heavy."

Waller said luck in running was the difference between Zoustar and Vilanova in the Sires'.

"Full credit to Jim Cassidy for ending up with a good trail on Zoustar while the second horse had to do a bit of work," he said.

"I think that was difference between winning and running second. The runner-up was posted three wide through no-one's fault and he's done a great job as well."

The long-term goal for Zoustar will be the Coolmore Stud Stakes (1200m) for three-year-olds at Flemington on Derby day.

"I want to keep the speed in his legs because the Coolmore is an ideal race for him," Waller said.

Cassidy said Zoustar was able to use his tactical speed to settle just behind the speed before hitting the lead at the 200 metres.

"The tempo slowed up mid-race but I was able to get a gap at the right time and he won like a really good colt," he said.

"I won on him at his first start at Canterbury and he's kept taking the next step."

Damian Browne said Missy Longstocking, who finished ninth as a $3.60 favourite, wasn't suited by the muddling pace.

"It was a stop-start race all the way and she couldn't get a run at the 200 metres when I was looking to improve," he said.

"She pretty much went to the post untested and I wouldn't write her off because things just didn't pan out for her."