The Fastnet Rock colt has won two of three starts this term, culminating with victory in the Champagne Stakes on St Leger day at Doncaster last month.
The horse, bred by the Skipton-born trainer’s father-in-law Lester Piggott, who remains one of the colt’s co-owners, worked on the gallops yesterday.
“He’s a good mover and dry ground will suit him well,” said Haggas. “I thought the win last time was laboured, but I think the ground was a bit loose for him. He’s got a bit to find to win a Dewhurst on that run.”
Rivet could clash with Churchill in the seven-furlong feature, with Aidan O’Brien’s runner arriving with four wins from five starts.
Meanwhile, Frankie Dettori does not see O’Brien’s feat of training the first three home in the Prix de l’Arc de Triomphe being matched.
Dettori played his own part as he rode Ascot Gold Cup winner Order Of St George into third place at Chantilly behind stablemates Found and Highland Reel.
“I’m part of history, I don’t think it will be done again,” said the jockey. “Having three runners in the Arc is hard enough, but to have the one-two-three is beyond belief.”