Dwayne Dunn has regained the lead in the Melbourne jockeys' premiership after guiding talented mare Miss Promiscuity to her first Group victory in the Sir John Monash Stakes.

And Dunn's win in the feature race at Caulfield on Saturday took on extra importance in the title race because Craig Williams had been booked to ride Miss Promiscuity before he was suspended.

Williams started the day one win ahead of Dunn and two ahead of Damien Oliver but is in front after a double.

Oliver won on Volcanic Ash and many expected he would make it a three-way tie for the premiership lead after the Monash Stakes because he had the ride on the favourite Lord Of The Sky ($2.35).

But Lord Of The Sky's race was over when he scrambled out of the barriers and he couldn't lead before finishing seventh.

In contrast, Miss Promiscuity ($12) began quickly from her wide gate and parked outside Wild Rain and Angels Beach.

As the field stayed away from the inside, Miss Promiscuity took over early in the straight and put 2-3/4 lengths on Wild Rain and Angels Beach who dead-heated for second.

Dunn had never ridden Miss Promiscuity but believes she's capable of winning even better races now she has scored a black-type win.

"When I began so well and I knew the favourite had missed the start, I was happy to be ahead of him," Dunn said.

"She travelled around the bend really well, found the right part of the track and she really gave a super kick."

Lord Of The Sky's trainer Robbie Laing said it was foreign to the horse to be behind the speed after his awkward getaway.

"His style is to lead and have them off the bit chasing," he said.

"It's disappointing, but we live to fight another day."

Dunn had got on the board early with victory on Pilly's Wish for trainer Mick Price.

"There's a little while to go yet (in the premiership) but it's going to be a good battle all the way to the end," Dunn said.