A horse whose racetrack appearances are accompanied by considerable trepidation among his handlers is set to make the risks seem worthwhile in Saturday's Doncaster Prelude at Randwick.

Mahisara showed himself to be a horse with a future when he won the Sandown Stakes in Melbourne last spring and his trainer Paul Messara believes he is ready to live up to the tag.

But there is a problem of raceday manners to overcome first.

"He's not bad at all until he gets to the races," Messara said.

"Then he gets excited, very colty. He can be his own worst enemy.

"But he has a lot of ability."

Mahisara heads betting on the race in which he will be ridden by Craig Williams and for which he is a $5 favourite.

A winner at four of his past six starts, Mahisara showed good promise early in his career but only achieved consistency last spring.

Messara put the improvement down to experience and with his first-up fifth in the Newcastle Newmarket behind him he is expecting even more on Saturday and more again in next week's Group One Doncaster Mile.

But in a race that is dominated numerically by imported gallopers and trainer Chris Waller, Mahisara will have stiff opposition from several directions.

Waller has five runners engaged, all of them imports, and most of them with Queensland missions in mind.

Early markets suggest English import Beaten Up is the pick of Waller's quintet and the trainer suggested he and Irish-bred galloper Class Is Class could run "cheeky" races.

Waller will also run the German import Illo, previously a member of the Bart Cummings team where he was held in high regard.

Waller said the horse had pleased in a trial at Randwick this week but was still adapting to Australian racing.