Sacred Falls has continued his love affair with the Randwick mile, adding the Group One George Main Stakes to his two Doncaster wins.

His first weight-for-age victory heralded a two-state Group One double on Saturday for trainer Chris Waller with Foreteller taking out the Underwood Stakes in Melbourne shortly afterwards.

Reunited with his 2014 Doncaster-winning jockey, Hong Kong's leading rider Zac Purton, Sacred Falls, the $4 favourite, threaded his way through the pack to beat stablemate Royal Descent ($6.50) by 1-1/4 lengths.

Waller thought he had said goodbye to Sacred Falls after his second to It's A Dundeel in the Queen Elizabeth Stakes in April.

But the horse's owners decided to delay a stud career in favour of another season's racing and Waller said he believed Sacred Falls was getting better as he got older.

"He could have been in the breeding barn but he's here winning Group One races so it's full credit to his owners," Waller said.

"And it's good to see him do it on a good track and prove he's not just a wet tracker.

"It's his fourth Group One win and they've all been over a mile but I think he's going the right way to get 2000 metres in the Cox Plate.

"One of his career-best runs was when he came second to It's A Dundeel in the Queen Elizabeth.

"He's bang-on for Moonee Valley."

Royal Descent is also headed to the Cox Plate after filling the runner-up position for the third consecutive time this spring.

"She seemed to over-race a little," Waller said.

"But we will press on to the Cox Plate. I don't see any reason to deviate from that plan."

The third of the Waller runners, Hawkspur, finished fourth, just behind Laser Hawk.

"Hawkspur will also go to Melbourne. He might be a horse for the Mackinnon or the Cox Plate," Waller said.

Purton, who made a flying visit to Sydney to ride Sacred Falls, said the Cox Plate was within his reach.

"He is definitely getting better," Purton said.

"He is a serious miler but he is definitely up to a Cox Plate."

Sacred Falls has been elevated to the second line of Cox Plate betting at $12 behind Dissident and Fawkner at $10 while Foreteller is a $15 chance.