Fiveandahalfstar moved closer to a possible start in next week's Victoria Derby with an all-the-way win over 1800 metres at Rosehill on Saturday.

The Anthony Cummings-trained three-year-old has had support for the Victoria Derby (2500m) with his odds cut to $19 after his win at Canterbury 10 days ago.

With Cummings in Melbourne for Cox Plate day, foreman Barry Smith said he was unsure of the trainer's plans but was pleased to see the way Fiveandahalfstar relaxed for Peter Robl at Rosehill.

"He relaxed beautifully today and it was good to see him finish it off," Smith said.

"He's always had ability and he's going to get better as he gets older.

"I'm not sure what Anthony is going to do with him."

Fiveandahalfstar ($3.80) had the measure of Rowie ($4) by 2-3/4 lengths with Bradman ($4.80) a long neck third with favourite Queen's Elect ($3.60) fourth.

If Cummings elects not to take on the blue riband at Flemington next Saturday there is an 1800m race five days later that has also been flagged.

Robl said although Fiveandahalfstar had had 14 starts he was still a touch immature.

"He's still on the upward spiral and he'll really come into his own as a four-year-old," Robl said.

"He still gives you that feeling he's a touch immature but he's definitely on the upward spiral."

It took the gelding until his 13th start to win a race but he had two minor placings behind Derby third favourite Honorius as a two-year-old.