Caleb Ewan took victory on stage five of the Giro d'Italia as a crash-strewn finish in Cattolica ended the general classification hopes of Mikel Landa and Pavel Sivakov.

Australian Ewan took his fourth career Giro stage as he came from behind to outsprint Giacomo Nizzolo and Elia Viviani on the line – an 11th career second place in his home Grand Tour for the winless Nizzolo.

But Bahrain-Victorious’ Landa did not finish the stage and left the race in an ambulance after a heavy crash involving Tuesday’s stage winner Joe Dombrowski on the approach to town, crucially outside the three kilometre marker which would have spared those caught up any time losses.

Israel Start-Up Nation’s Alessandro De Marchi avoided the spills to retain the pink jersey but called the tight, technical finish to the 177km stage from Modena "a crazy circus".

"The road was really difficult and technical, even too dangerous in my opinion so in the last 70km there was really a lot of stress and I hope the guys that crashed are fine," he said.

De Marchi's Irish team-mate Dan Martin (33rd) finished safely in the bunch and moved up two places to 19 in general classification, 2:08 behind De Marchi, while Nicolas Roche was 69th in the same time and is now 58th overall.

Team UAE Emirates’ Dombrowski – second overnight – rode in battered and bruised on his 30th birthday, his king of the mountains jersey torn, as he tumbled down the standings, with Louis Vervaeke of Alpecin-Fenix now closest to De Marchi, 42 seconds down.

Sivakov, who had been a potential foil for Egan Bernal for the Ineos Grenadiers, also crossed the line in pain after his own incident 15km from the finish.

It was a dramatic climax to a relatively sedate stage, virtually pan flat and ridden in sunshine after Tuesday’s wet and cold day finish in the mountains.

The threat of crosswinds did not materialise to leave the sprinters to contest affairs, and it was Ewan who had the class to come around the two Italians and tick one box in his goal of winning a stage of all three Grand Tours this season.

"It was a relief," the Lotto-Soudal rider said. "My goal this year is to win in all three and the first sprint stage didn’t go so good, so there was a lot of pressure on me and all the team to do the job.

"They out-performed themselves, they were so good today and without them I couldn’t have been so fresh at the finish."

Bahrain-Victorious later said Landa was being treated in hospital after breaking his collarbone and multiple ribs on his left side.

X-rays for Dombrowski came back clear but the American will be assessed for concussion before Thursday's 160km stage six from Grotte di Frasassi to Ascoli Piceno.