American Group One winner Unusual Suspect has finally cracked it for a win in Australia, taking out Sunday's Werribee Cup.

The nine-year-old has run in two Melbourne Cups since joining Mick Kent's Cranbourne stable almost two years ago but showed his best form before Sunday when third in last month's Sandown Cup.

"It's not his fault. This is probably the first race I've run him in where he's had a realistic chance, Kent said.

"We took him to Dubai and it was disastrous.

"His runs in both the Caulfield and Melbourne Cups last year were really good. He ran in the Moonee Valley Cup this year and was terribly in under the set weights and penalties.

"And the (2012) Melbourne Cup was a waste of time the way it was run."

Brad Rawiller settled Unusual Suspect at the back of the six-horse field and bided his time until the home turn in the 2600m feature.

Unusual Suspect made a late surge to claim King Diamond by a half head with I'm Jake a head third.

"It's fantastic to win the Cup and such a great pleasure to win on this horse," Rawiller said.

"For a long time he's been up and threatening to win.

"I had him in a good rhythm the whole race. I had a lovely flow-on run and it was a big effort by him."

Unusual Suspect latest win before Sunday was the Grade One Hollywood Turf Club Cup in November 2010.