He has been the bane of jockeys and barrier attendants, but Maurus can confirm his coming of age in an important spring staying test at Rosehill on Saturday.

The five-year-old steps up to black-type company for the first time in the Group Three Kingston Town Stakes, a race his trainer David Vandyke has twice won with similarly progressive stayers Lamasery (2011) and Prince Cheri (2013).

The journey with Maurus has been a frustrating one for Vandyke who admits the horse has challenged him on several fronts.

"This boy Maurus, he's a very unique type of horse. He's a real fighter on and off the track," Vandyke said.

"He was cantankerous and always tried to throw his riders.

"At one point he was barred from racing because he wouldn't start, he would just stand in the gates.

"He has tested all of us so to see him in this sort of form is a wonderful reward for all the effort."

Vandyke admits Maurus remains a "work in progress" but the horse is learning to channel his energy.

He has won his past two starts, the latest over 1900m at Canterbury off a 10-week break when he lumped a big weight and showed the same fighting qualities that almost brought his career undone.

Maurus faces his toughest test on Saturday in a race which will determine whether Vandyke aims towards next month's Metropolitan or lowers his sights.

He is a $7.50 chance with betting dominated by stakeswinner Silverball who has firmed into a $1.85 favourite ahead of Godolphin's Havana Cooler ($6) which backs-up after failing to handle the soft, tight-turning track in the Wyong Cup.