Durston has made the most of a last-minute inclusion to give champion Australian trainer Chris Waller a second Caulfield Cup triumph.
Left as the the first emergency for the $5 million race when the field was decided, Durston was elevated into the famous handicap with a race morning scratching.
In a pulsating finish, Durston arrived late on the scene for jockey Michael Dee to snatch the race away from topweight Gold Trip.
Knights Order made most of the running before filling the minor placing.
Durston was one of four Caulfield Cup runners for Waller, who first won the race with champion mare Verry Elleegant in 2020.
Favourite Smokin' Romans was given every chance by jockey Jamie Kah.
He loomed into the race on the turn before switching back to the inside of runners but conceded ground late to finish just behind the placings.
