Big-race jockey Glen Boss produced a magical ride to win his fourth Cox Plate on imported galloper Sir Dragonet and now he's hoping the horse can also provide him with a fourth Melbourne Cup.

The victory was also a triumph for the training partnership of Ciaron Maher and David Eustace who celebrated their first Cox Plate success.

Maher rated it as the highlight of his career.

"It's something else. You dream of having a runner in it, let alone winning the race," Maher said.

Maher confirmed Sir Dragonet would press on to the Melbourne Cup and said the job was only half done.

Sir Dragonet was purchased from Coolmore by an Australian syndicate headed by Ozzie Kheir after he finished second to Magical in the Curragh Gold Cup in July.

"Ozzie bought him for the Melbourne Cup and he'll be even better in that race," Maher said.

Boss celebrated in style and in his traditional manner, stood high in the irons and gave a fist pump as Sir Dragonet hit the line.

He was later fined $1000 by Racing Victoria stewards for his celebration and also $1000 for breaching COVID protocols by hugging stable staff.

Boss settled Sir Dragonet midfield and he produced him at the right time in the straight, just when Armory and Russian Camelot looked to be fighting the race out.

Sir Dragonet ($7.50) scored by 1-1/4 lengths over Irish raider Armory ($7.50) with Russian Camelot ($3.50) another three-quarters of a length away third.

Boss said he couldn't believe he had joined Hugh Bowman and Brent Thomson as the most successful Cox Plate jockeys with four wins.

"It's unbelievable. I used to wear out my VCR watching the Kingston Town and Manikato video. It's ingrained in my psyche," he said

The 51 year-old Boss has rejuvenated his career in the past 12 months and said he had become calmer with age.

Boss is also confident he can take his Melbourne Cup tally to four on Sir Dragonet as he predicted he might even go better in that race.

"I couldn't have scripted it any better. I knew he was travelling well and he was up to the task," Boss said.

Boss thanked Hugh Bowman, who would have ridden Sir Dragonet bar for suspension, for pushing for him to ride the horse.

"When Hugh was suspended I rang up Ozzie and presented my case," Boss said.

He also praised recently-retired jockey James Winks who had been riding Sir Dragonet in trackwork and gave him advice about the five-year-old stallion.

Danny O'Brien said Russian Camelot produced the best run of his career to finish third and would also head to the Melbourne Cup.

"I was really proud of him. He went forward from a hot tempo and Damien Oliver gave him a superb ride," O'Brien said.

"He was left a sitting shot but kept on fighting."

Ben Melham was pleased with the run of second placegetter Armory and said he struggled on the wet ground.

The unlucky runner was Arcadia Queen who almost fell with 1000 metres to go.

Jamie Kah made it a memorable Cox Plate day riding four winners, opening her account on Sneaky Five before adding victories aboard Sovereign Award, Miami Bound and La Mexicana.