Mongolian Khan has given master Kiwi trainer Murray Baker his first Caulfield Cup (2,400m), using his superior stamina to claim the $3 million race.
The victory was well received by punters who backed Mongolian Khan into $5 favouritism after his bold third in the Caulfield Stakes a week ago.
Bosson settled the four-year-old in the first half of the field and made his move to attack the leaders approaching the turn.
The plan was to make it a stayer's race in the straight. We know he can run 2,400m and it worked out," Baker said.
"He's a very good stayer. I think at 2,000m in weight-for-age he isn't sharp enough to manoeuvre out, but we knew he would stay today at 2,400m."
Baker had placegetters in three Caulfield Cups before Saturday, finishing third with The Phantom (1989) and second with Nom De Jeu (2008) and Harris Tweed (2010).
"I've been coming here for a while. I think they gave me one for good attendance," Baker said.
"It's one I wanted to win. The strongest 2,400m handicap in Australasia — it's a great race and it's a privilege to be here."
It was Bosson's first ride in the Cup and was "by far my biggest thrill in racing".
"He was beautiful and relaxed. He cruised through it when I wanted him to — 2,400 metres, he eats it up," Bosson said of Mongolian Khan.
"He could go again. He loves staying and look out the Melbourne Cup.
"A big thanks to Murray and the team. I can't believe it won.
"I want to thank everyone, my parents, and they will be so happy, and my girlfriend Emily has been supporting me hard, getting my weight down and making sure I eat properly. Everything is paying off.
Baker confirmed Mongolian Khan would go straight to the Melbourne Cup at Flemington on November 3.
"That will be the plan," he said.
But now he and connections must await the decision on a penalty from Racing Victoria chief handicapper Greg Carpenter at 11:00am (AEDT) on Monday.
Mongolian Khan also has to overcome history as no Australian Derby winner has returned as a four-year-old to win the Melbourne Cup since Phar Lap in 1930.
The connections of Trip To Paris were thrilled with the performance of the Ascot Gold Cup (4,000m) winner who was not expected to get warm over the 2,400 metres on Saturday.
But the five-year-old, trained by Ed Dunlop, recorded the fastest final sectionals of the race.
"Fantastic. I couldn't believe it. It was a marvellous run," said Robin Trevor Jones.
"But always remember there is a big chestnut this time next door to him, he's got to beat that one," he added in reference to ageless marvel Red Cadeaux, who is back for a fifth Melbourne Cup.
Damien Oliver said the well-credentialed English runner Snow Sky ($9, fifth) had a beautiful run before the turn but lost momentum when trying to get clear at a crucial stage entering the straight.
"He worked to the line nicely. It was a good Melbourne Cup trial and Flemington will suit him better," Oliver said.
Kris Lees, meanwhile, reported last year's Melbourne Cup winner Protectionist ($51, 15th) had pulled up a little scratchy from Saturday's run and there are serious doubts over whether he will press on to Flemington.