Sydney's all-conquering trainer Chris Waller was second guessing himself after deciding to send Good Project to the races off one barrier trial.

But the horse proved his trainer's instincts to be spot on when he resumed with a powerful victory in the Mack Trucks Handicap at Rosehill.

"He trialled outstanding which is why I ran him without a second trial," Waller said.

"I didn't know if I did the right thing or not, which you don't until race day."

Returning from a mixed campaign in Brisbane that left Waller with more questions than answers, Good Project stalked a solid speed and showed his class to stave off the challenge of a race-fit Inz'n'out by three quarters of a length.

Drifting favourite Music Magnate briefly raised the hopes of his backers but peaked on his run inside the final 200m to finish third another 1-1/4 lengths away.

Waller has no major plans for Good Project, whose win ensures he avoids being gelded, at least for now.

"I left Queensland thinking `is he the real deal or not?' and today was a good stepping stone to him hopefully going on to better things."