Kris Lees is convinced Protectionist will relish getting back to Flemington but the trainer is wary about the horse's chances of adding an Australian Cup to his Melbourne Cup win.

Protectionist will be out to join Fiorente, Makybe Diva and Let's Elope as horses which have won the Melbourne Cup and the Australian Cup at weight-for-age in the same season.

The stayer was doing his best work late in the Peter Young Stakes at his first start for Lees when beaten four lengths in sixth place.

Lees is banking on horses such as The Cleaner making it a genuine 2000-metre test on Saturday.

"He's very well in himself," Lees said.

"We've always been pretty open that we're guarded about him over the shorter trip but all the natural things, the extra 200 metres, the bigger track and genuine tempo are all things that are going to suit him.

"It's just whether he can react at the 2000 metres."

Lees said Protectionist would definitely improve from Caulfield, which he rated the run strong enough to press ahead with Australian Cup plans.

"I expect him to run very well, but I think he's false favourite," Lees said.

Happy Trails has displaced Protectionist at the top of betting, firming from $6.50 to $4.80 since Tuesday.

Protectionist has eased from $4.80 to $5.

Peter Young Stakes winner Mourinho is in career-best form and is at $9 along with Spillway.

Protectionist's Melbourne Cup win was one of the easiest of the modern era when he scored by four lengths over Red Cadeaux, a rival on Saturday.

Happy Trails will be chasing his fourth Group One win at the track having won the 2012 Emirates Stakes, the 2013 Turnbull Stakes and last year's Mackinnon Stakes.

The Chris Waller-trained Foreteller is also a Group One winner at the track in the 2013 Makybe Diva Stakes.