Veteran British sprinter Mark Cavendish has had an almost constant smile on his face at the Tour de France where Friday's route and finale appear to be a perfect platform for him to put claim to a famous record.

Cavendish shares the all-time Tour de France stage win record with Eddy Merckx, but the Bordeaux finish line looks tailor made for the Manxman to establish a new record of 35.

"It's flat, super-flat and easy for the teams of the sprinters to control," race designer Thierry Gouvenou told AFP Thursday.

It also has a 2km long home straight, the kind of stage finale where Cavendish crushes all comers.

The 38-year-old reached 73kph at one point on the first bunch sprint on stage three in Bayonne, where he came sixth. No rider has gone faster so far at the Tour.

At the Nogaro motorbike racetrack on stage four he came fifth, and said he'd been blocked by a fall as the 25-year-old Jasper Philipsen won a second straight stage.

Ahead of that stage 94-year-old former rider Andre Darrigade, winner of 22 stages himself, predicted that Cavendish would eventually break the record, but put that record into perspective.

"Breaking the record would in itself be incredible, but Eddy Merckx won five Tour de France too, and that makes the two incomparable," Darrigade told AFP.

Cavendish has been saying the same thing ever since joining Merckx on 34 wins in 2021.

"I know what it's like to win a Tour de France stage, and I've known it 34 times," he said in Bilbao ahead of the Tour, where a Netflix television crew for a series to be aired in August is following his every move.

Another man following Cavendish's every move is the Australian Mark Renshaw, his former lead out man for sprints who is now sprint consultant for the Astana team.

Renshaw told AFP he also believes in Cavendish's chances of breaking the record with a 35th win, even if he has to wait for stage 21 on the Champs Elysees.

"Come race day in Tour de France he is just a different rider. He can go harder, he can go deeper, he can suffer more than anyone," Renshaw said.

"I've never seen another rider grow with the pressure and the race as much as him.

"He needs a team to commit to him," says Renshaw. "If the team give him that he can't stand being the weak link so he gives even more," he explained of Cavendish's mental attitude.

Tour de France director Christian Prudhomme suggests that whatever happens Cavendish has nothing left to prove to anyone.

Cavendish scorched into the cycling limelight back in 2008, celebrating his first four Tour de France stage wins 15 years ago.

Perhaps his greatest achievement was fighting back from the debilitating Epstein Barr virus to carve a glorious Indian Summer in 2021 at Quick-Step, which he considered his spiritual home.

"The stars didn't align for me, that was me burning my fingers moving them," he said at the time.

"Can he do it? I think he can," Alberto Contador, twice a Tour de France champion, said ahead of the Tour.

"His morale will be at an all-time high after winning a stage on the Giro," he said of Cavendish's stage 21 win in Rome in May.

Having said in May that he planned to retire after this season, on Thursday, he left the door ajar for another year when asked when his last race would be.

"I'm still racing, still loving it, and I'll keep doing it until I stop," he said.

"The biggest thing I can say is never give up, do what you want and enjoy it, but commit to it."

Stages eight and 11 are also tantalising sprint opportunities but barring that stage 21 to the Champs Elysees presents one more opportunity at the iconic cobbled avenue where he has roared in triumph on four previous occasions.