Mark Cavendish continued his hot streak in the Tour de France yesterday to claim his fourth stage victory in this year's race, winning the 113-mile thirteenth stage from Narbonne to Nîmes.

Twenty-four hours after his victory in Narbonne, the 23-year-old's fourth win was almost expected, so dominant has the rider from the Isle of Man become on the Tour's flat stages. Yesterday he held off Robbie McEwen, the experienced Australian sprinter, in the dash to the line and, despite being poorly positioned in the final 200 metres, the Briton's surge of speed got him across the line first, arms aloft. “Yet again the team did a perfect, perfect job and dropped me off at the finish,” Cavendish said. “It seemed a long way to that finish line, but I made it.”

From a British perspective, his success is unprecedented. Only Barry Hoban's victories in two Tour stages in 1969 and 1973, compares with Cavendish's achievement. Already in his second Tour, Cavendish ranks alongside legendary sprinters such as Mario Cipollini and Freddy Maertens, both multiple stage winners in the European tours.

But as the Briton celebrated, the doping scandal involving the Saunier Duval team and Riccardo Ricco, their leader, took another turn when it was revealed that Leonardo Piepoli, Ricco's team-mate and the winner of the Pyrenean mountain stage to Hautacam, had been sacked by his sponsor after an internal investigation. Piepoli's dismissal means that all three of Saunier Duval's stage wins have been discredited.

“We've always controlled our athletes as much as possible, expecting them to behave correctly,” Mauro Gianetti, the team manager, said in a statement. “Contracts are always drawn up with strong ethical clauses and we have guarantees from the riders. Ricco swore on his mother's honour that he would never have used illegal practices.”

Ricco, meanwhile, has pledged to clear his name.