Victorian jockey Ben Melham has produced a stunning Sydney raid, saving his best performance of the day for an upset win on Sense Of Occasion in the Group Two Villiers Stakes.

Sent out a $31 chance, Sense Of Occasion's win in Saturday's feature race over 1600m at Randwick even took trainer Kris Lees by surprise.

It was the third leg of a treble for Melham who also won the $500,000 Inglis Classic on She Will Reign and scored aboard Kinshachi in a benchmark handicap.

"I thought this would be a nice lead-up into a Gosford Cup but he's really trialled well and he's impressed us in all his work," Lees said.

Lees said he instructed Melham to ride Sense Of Occasion quietly and try to find a late run.

"I rode him as hard as Ben Melham the last 100 metres," Lees said.

After settling last, Melham rode for luck and found the crucial gap before the 100m mark to poke through and consign Dibayani ($9.50) to the ninth Group placing of his career with Sarrasin ($21) third.

Dibayani, who hasn't won since June 2013, looked the winner at the 150m until he reaffirmed his bridesmaid tag.

"He was going all right until he saw the winning post. He's just a little camera shy," Dibayani's jockey Damien Oliver said.

While Sydney's racing treated Melham well, the city's hot weather didn't and he gave up the ride on Brook Road in the Razor Sharp Handicap after suffering dehydration.

Stewards inquired into the Villiers performance of $2.60 favourite Fabrizio after he finished last.

"He's had a long, hard preparation and probably showed signs of that today," Fabrizio's jockey Tim Clark told stewards.

"He's looking for somewhere to lie down and that was at the furlong."

Sense Of Occasion's win gave Lees a welcome conundrum as he weighs up whether to try for the $100,000 bonus for winning the Villiers and Bernborough Handicap (1600m) at Doomben on New Year's Eve or stick with his original plan of the Gosford Gold Cup on January 13.