Anthony Cummings' Golden Slipper hopes have been boosted by the win of Never Can Tell at Rosehill with the colt upsetting the highly touted Whittington in the Canonbury Stakes.

The winner of his debut in October, Never Can Tell ($8.50) wore away at the $2 favourite to prevail by half a length.

Both the colt's wins have been at 1100 metres but Cummings doesn't believe he will have any trouble with the extra 100 metres of the the upcoming juvenile features including the Slipper on April 6.

"He did a good job at his first start and had a good break afterwards," Cummings said.

"We can pick and choose how we get to the Slipper. At 1200 metres he will be better again.

"He has shown he can switch off and switch on again which is a good attribute to have."

Never Can Tell is by War Pass, the 2007 Breeders' Cup Juvenile winner, who stood for just two seasons at Widden Stud before his premature death in the United States.

The colt is owned by Eduardo Cojuangco's Gooree Pastoral Company which raced Smart Missile who was pushing eventual winner Sepoy for favouritism in the 2011 Slipper.

Smart Missile didn't get the chance to show if he could have pushed Sepoy, being scratched at the barrier after a horse played up in the stall next to him.

Trainer Gai Waterhouse was upbeat about Whittington despite his defeat.

"He was competitive," she said.

"The two colts cleared away from the rest."

Criterion ($9) finished third, 2-1/2 lengths from Whittington with Napayshini ($5.50) disappointing beating just one home after coming out of the gates last.