Australian Derby winner Jon Snow has shown he is on track for the Caulfield Cup with victory in the Group Three JRA Cup at Moonee Valley.

The New Zealand stayer was having his third start of the spring in Melbourne in Friday night's race, stepping up from 1600m to 2040m and dropping back from Group One company.

With Stephen Baster aboard the four-year-old sat off leader Kilmacurragh before taking over as they rounded the turn.

Ecuador emerged on his outside to challenge but the Derby winner was strong to the line, winning by three quarters of a length with another length to third-placed Boom Time.

Jon Snow finished sixth in the Memsie Stakes (1400m) and eighth in the Makybe Diva Stakes (1600m) before getting to a more suitable distance.

"He did it quite well," Baster said.

"Obviously getting to the trip suits him. He was nice and relaxed and looks better every time I ride him.

"He's just a good horse."

Murray Baker, who trains in partnership with Andrew Forsman, said Jon Snow was on a path to the Caulfield Cup and would likely have one more run, with the Caulfield Stakes (2000m) and Herbert Power Stakes (2400m) the options.

"That was pleasing," Baker said.

"We thought he would go a bit better tonight. He needed the distance.

"It was probably too short for him the past two starts but he's improved a lot in the last couple of weeks.

"He's a good stayer.

"He's a similar type of horse to Harris Tweed."

Baker trained Harris Tweed who was second in the 2009 Australian Derby and 2010 Caulfield Cup and ran fifth in two Melbourne Cups.