A half-brother to dual Group One-winning mare Red Tracer has broken through for his maiden success at Moonee Valley.

The victory on Wednesday in the Telstra Business Centre Melton Plate (1200m) may have also delayed a trip to Singapore for Duty First.

Ridden by Craig Newitt, Duty First ($4.60) scored a comfortable 1-1/4 length win from Saving Winston ($12) with Expressamosa ($3.70) 5-1/2 lengths away third.

Justine Hailes, the Melbourne representative of trainer Chris Waller, said Duty First was highly thought of as a younger horse but needed gelding to bring out the best.

"They had quite a big impression of him when he was younger but some of the boys said he was a bit colty and that was why he got gelded," Hailes said.

"Hopefully now that he's had a win he might switch on a bit more.

"They were thinking that he might have been going to Singapore but hopefully he'll stay here now for a bit longer with the cut in the ground, but if he goes up there the cut in the ground will suit him also."

Hailes said while Duty First had taken time to finally break through for his first win, the dam Kisma has been a good producer.

"This one and Counterattack have a bit of size about them which may turn out well for them," Hailes said.

"The mare has been a good producer with Red Tracer and Shellscrape, and Counterattack looks like he might be the goods also."