ASTI, ITALY -- Dutch rider Wilco Kelderman remained the overall leader of the Giro d'Italia heading to the final two days but Josef Cerny's stage win was overshadowed by rider protests at the start on Friday, and race director Mauro Vegni hinted at legal action.

The route was slashed in half shortly before the start in Morbegno.

It was meant to be the longest stage of the race, at 258 kilometres (160 miles), but riders were upset at having to endure such a lengthy stage in poor weather conditions in the third week of the Giro and sandwiched between difficult mountain stages.

"It's a decision that we put up with, we didn't accept it," Vegni said. "We'll finish the Giro and then when the dust settles someone will pay.

"Today, as a sport, we were an embarrassment, after having done so much work to successfully carry out a difficult Giro."

Ineos Grenadiers was one of the teams reportedly keen to set off but others pressed for the route to be altered and organizers eventually agreed. The peloton rolled out from Morbegno in a downpour but stopped after eight kilometres (five miles) to wait for team buses to transfer them to the new start in Abbiategrasso.

"A lot of the riders didn't agree, but it only needs someone to start saying something," Vegni said. "Some people are saying that the request was made yesterday but I only knew today.

"You can't have discussions 15 minutes before the start. Or you have to stop the race or just a few would have set off and it would have been a further embarrassment. But the story won't end here, we'll get to Milan and someone will pay."

Cern├╜, a Czech rider with CCC Team, soloed to his first victory in a Grand Tour at the end of the 124-kilometre (77-mile) route to Asti.

He launched his attack from a breakaway group about 20 kilometres (12 miles) from the finish to beat Victor Campenaerts by 18 seconds. Jacopo Mosca won a sprint for third, 26 seconds behind.

Kelderman remained 12 seconds ahead of Team Sunweb teammate Jai Hindley. Tao Geoghegan Hart was third overall, 15 seconds behind.

"I've enjoyed every minute wearing the Maglia Rosa (pink jersey) today," Kelderman said. "I'm quite confident I can retain it tomorrow as well.

"This morning the weather was bad, it was very cold. This week has been tough and it's risky for our immune systems. I am grateful to (the organizers) for listening to us and for having shortened the stage."

Saturday's penultimate stage was altered earlier in the week, cutting out two of the most difficult climbs of the race.

French authorities withdrew their permission for the Giro to cross into France because of new restrictions following a spike in coronavirus cases in the country.

The 20th stage will no longer go up the Colle dell'Agnello and cross into France for the Col d'Izoard, but will instead climb to Sestriere three times on an altered 190-kilometre (118-mile) route.

The Giro was rescheduled from its usual May slot because of the coronavirus pandemic. The race ends on Sunday with an individual time trial in Milan.