Movistar's Richard Carapaz held on for victory on stage four of the Giro d'Italia in Frascati but Primoz Roglic was the big winner as a late crash hit his rivals and saw him extend his lead in pink.

A touch of wheels a little over five kilometres from the finish saw several riders hit the deck and caused a shake-up of the general classification.

There had been much speculation as to whether the slight uphill finish would suit a sprinter or a punchier rider but in the end only a small group was left to contest the stage, with Roglic and Carapaz the only one major general classification hopefuls among them.

Mitchelton-Scott's Simon Yates was in the next group on the road alongside Vincenzo Nibali (Bahrain-Merida), Miguel Angel Lopez (Astana) and Bob Jungels (Deceunick-QuickStep), conceding 16 seconds to Roglic, but the big loser was Dutchman Tom Dumoulin.

The Team Sunweb rider, second in this race last year, already looks out of the reckoning this time around as he crossed the line more than four minutes after Roglic, bleeding heavily from his left knee.

Roglic now leads by 35 seconds from Yates, with Nibali a further four seconds back.

The win could also bring Carapaz back into the reckoning after a disappointing opening time trial, with the bonus seconds leaving him 81 seconds off pink in 16th place.

Yates' fellow Lancastrian Hugh Carthy of EF Education First is 13th, 76 seconds down, while Team Ineos' Pavel Sivakov sits in 17th, 84 seconds back as the team's best-placed rider.

The crash completely split the peloton with only seven riders left in the front group to contest honours at the end of the 235km stage from Orbetello.

Carapaz attacked in the final few hundred metres and though Lotto-Soudal's Australian sprinter Caleb Ewan set off after him, the Ecuadorian had just enough to hold on.

For the second straight day, it was a nervy, chaotic finish to end what had been a long, slow day with riders taking it easy over the rolling 235km stage.

An all-Italian three-man break formed of Marco Frapporti (Androni Giocattoli-Sidermec), Marco Maestri (Bardiani CSF) and Damiano Cima (Nippo-Vini Fantini-Faizane) had been allowed a lead which stretched to 11 minutes at one point but the peloton stepped up the chase in the final third of the stage.

The catch was made with 10km to go but moments later came the crash which could yet prove pivotal in this Giro.