Trainer Steve Richards is relying on extra distance to bridge the gap between Justaway and his debut conqueror in Saturday's Eugene Gorman Handicap at Flemington.

The Mark Kavanagh-trained Callahan finished 2-1/2 lengths ahead of Justaway when the pair met over 1100m at Seymour on May 26.

But the two-year-olds will compete over 1400m at Flemington and Richards believes Justaway will appreciate the rise in distance.

"The 1100m was always going to be a bit short for him but we didn't worry about that when we took him there because it was all about giving him the experience of a race," Richards said.

"Callahan is a smart horse and he'll be hard to beat but my bloke will run well. He's going through his education pretty well."

Justaway has pleased Richards with his improved work since his debut fifth but the trainer said he would handle the son of French Group One winner Thewayyouare conservatively.

Richards said Justaway would also be effective over 1600m but he could wait until next season to test the gelding over that distance.

"He might be in the paddock after this but he's going to be a better three-year-old," Richards said.

Callahan has opened as a clear $2.20 favourite to remain unbeaten at Flemington while the TAB rated Justaway as a $10 chance to repay the $NZ40,000 ($A38,000) Richards paid for the youngster at a New Zealand yearling sale last year.

Richards bought the impressive juvenile Marcado at the same sale and the Choisir gelding is back in work for his spring three-year-old campaign.

Marcado won the Listed Talindert Stakes in smart fashion on debut before running a solid third to Zululand in the Group Two VRC Sires' Produce Stakes.

Richards said Marcado could resume in either the Group Three Vain Stakes at Caulfield or the Listed Mitchell McKenzie Stakes at Moonee Valley in August.

"He looks terrific and strong as an ox and he did really well in his spell," Richards said.

Stable jockey Steven King will ride Justaway at Flemington.