Five-time Tour de France winner Bernard Hinault believes defending champion Tadej Pogacar will be difficult, but not impossible to beat.

Hinault won the Tour in 1978, 1979, 1981, 1982 and 1985, and told AFP in an interview in Dunkirk on Tuesday that Pogacar is a very strong favourite indeed.

Twenty kilometres of cobbles on Wednesday is the Tour's first real challenge, and the last Frenchman to win the Tour de France insists Pogacar will have no problems there despite his slender frame.

"It could be the start of the real Tour de France, quite simply because you can have falls, punctures, all kinds of race incidents meaning the Tour could be lost or won here," said the 67-year-old.

"So normally you'd have to be really vigilant even if it looks like there won't be any wind or rain," he said of stage five between Lille and Arenberg.

This stage features 11 sections of cobbles along the old mining roads used in the one-day classic Paris-Roubaix race known as "The Hell of the North".

"Pogacar has already shown he can deal perfectly well on cobbles after his performance on the Tour of Flanders, where he came fourth," Hinault explained of the nail-biting Belgian cobbled classic in April that Pogacar almost won.

"He's a guy who rolls well on the cobbles and is capable of pulling something off," he said of the Slovenian all-rounder who won the Tour in 2020 and 2021.

Known as 'the Badger' in his racing days due to his attacking attitude, Hinault suggested Ineos and Jumbo might do well to join forces to trap the two-time champion on his own and then mug him.

"If you want to beat Pogacar, you have to attack him and attack him in numbers. One rider attacking wouldn't be enough because he'd dominate that struggle," he insisted.

"So if you have a team with two or three riders in a team capable of attacking him, Pogacar's only solution would be to counter-attack and go on his own or give it up.

"Either Jumbo or Ineos could take Pogacar on, but only if they don't attack each other and only race against him."