A trip north and a slog over 2000m has been worthwhile for Assign at Rosehill as the stayer got more miles in his legs before a possible start in the Sydney Cup.

The Robert Hickmott-trained gelding made his first impression in this preparation by claiming the Group Three $150,000 Neville Sellwood Stakes on Saturday, in the six-year-old's second run since the Melbourne Cup.

Backing up from a last placing in the Mornington Cup Prelude on February 25, Assign withstood a fast tempo controlled by Classic Uniform before a rails run under Ben Melham enabled him to score by three-quarters of a length ahead of Astronomos, the $2.80 favourite.

Single Gaze ($10) was a short neck back in third.

"They went a bit quick from him early so I came back and let him find a rhythm. I put a gap on him at the top of the straight but I knew he'd keep coming," Melham said.

"Although this probably wasn't really his preferred surface (a heavy 9) ... he did a fantastic job to battle on and win."

Melham, who won last weekend's $3.5 million Golden Slipper on She Will Reign, missed the card-opening Schweppervescence, leaving Corey Brown to step in and salute on The Mission.

He was late arriving to the track after flying in from Melbourne and his fluctuating day could get worse, with stewards likely to censure Melham for extensive use of the whip.