Lloyd Williams-owned import Green Moon produced an upset performance to win the Melbourne Cup in front of a packed house at Flemington today.

Paying $20 at race jump, the six-year-old was largely ignored in the betting but produced a stunning performance to deliver prominent owner Williams his fourth Melbourne Cup.

Brett Prebble flew in from Hong Kong to assume the ride aboard the son of Montjeu and he produced a textbook Melbourne Cup performance.

Held just off the pace as Glencadam Gold set only a slow tempo up front, Green Moon travelled comfortably throughout the trip before being called upon by Prebble approaching the home turn.

In the straight he was the only one who truly looked the winner as he galloped clear to score a convincing win ahead of Gai Waterhouse-trained import Fiorente and international raider Jakkalberry.

Prebble was understandably delighted with the result and said he knew he was on the winner a long way from home.

“It’s the pinnacle of racing in Australia,” Prebble said.

“Today I’m going to go home and enjoy it.

“At the 1200m I knew nothing could go with him…I was very confident that they weren’t going to pick him up.”

Chris Waller’s import Kelinni produced a bold effort to run fourth after gaining qualification by winning the Lexus Stakes on Saturday.