BURY rider Adam Yates and fellow Brit Geraint Thomas' hopes of winning the Giro d'Italia suffered a major blow as both men were involved in a crash caused by a police motorbike 15km from the finish on today's stage nine, which was won by Colombia's Nairo Quintana.

Yates, who rides for Australian team Orica-Scott, ended the day in 16th place, 4mins 49secs off leader Quintana, while Team Sky's Thomas, who was second at the start of the day, finished over five minutes back.

"It is ridiculous and should not happen," said Thomas.

Despite the crash, Quintana put in a dominant display.

The Movistar rider finished 24 seconds ahead of Frenchman Thibaut Pinot and Dutchman Tom Dumoulin to take the race lead from Luxembourg's Bob Jungels.

The 2014 winner attacked with six kilometres to go as the race approached the summit of the steep Blockhaus climb and looked in a class of his own as he raced clear.

But behind him, Dutchman Wilco Kelderman was unable to avoid a police motorbike stopped at the side of the road and also swerved to his right into the Sky riders, who were in a line in the peloton, resulting in the majority of the British team being brought down.

Welshman Thomas stayed down for several minutes before being able to continue and later revealed his shoulder had "popped out".

"I'm a bit angry at the minute and need to work out what to do tomorrow," said Thomas, who has dropped to 17th in the standings, 5:14 behind Quintana.

"The bike had just stopped on the side of the road, we were all racing for position and someone in front of me hit it and we had nowhere to go, we all went straight down.

"I had felt good and then I crashed and my race was over, it is very disappointing."

Team Sky principal Sir Dave Brailsford told Eurosport: "A motorbike shouldn't have been there. I'm sure the guy who was riding the motorbike realises that too.

"We fight on. That's it."

There is a rest day tomorrow, before Tuesday's stage 10, a 39.8km individual time trial from Foligno to Montefalco.