Geraint Thomas' hopes of winning the Giro d'Italia were effectively dashed as Jonathan Caicedo won a third stage that blew the general classification race wide open.

Team INEOS rider Thomas crashed in the neutral zone prior to the 150-kilometre ride that began in Enna and was dropped from the peloton prior to the gruelling 19km climb up Mount Etna to the finish.

He finished 12 minutes and 19 seconds adrift of Caicedo and more than 11 minutes behind a group of GC contenders that included Vincenzo Nibali.

Simon Yates, another candidate to triumph in Italy, finished four minutes and 22 seconds behind Caicedo, who narrowly missed out on the maglia rosa to Joao Almeida.

Thomas appeared to only suffer superficial injuries when he went down prior to the start of the race, with the crash reportedly caused by a bottle falling loose in the bunch.

Filippo Ganna, who started the day in the pink jersey, helped his INEOS team-mate Thomas fight on until the end, but losing ground at the base of Etna may well have extinguished the Welshman's hopes of winning a second grand tour.

Caicedo was a late arrival to an early break and he hung on as others wilted, dropping Giovanni Visconti with 5km to go and charging on to glory.

"I can't believe it, it's a dream come true. It just goes to show that if you believe in yourself, you can do it," said Caicedo.

"I was with a rider [Visconti] with a lot of experience and plenty of Giros behind him. I tried to pace myself and time my attack well, and I had the strength to make it to the finish line.

"I came here for stage wins. I hope my body responds well, and I'll try again on other days."

Harm Vanhoucke claimed the remaining bonus seconds before Jakob Fuglsang led Nibali, Rafal Majka, Jonathan Castroviejo and Domenico Pozzovivo across the line 51 seconds after Caicedo. Steven Kruijswijk was a further five seconds behind.

Yates fell away with 9km remaining and Mitchelton-Scott only dropped one rider back to assist him, meaning he slipped three minutes and 46 seconds adrift in a dramatic day in the GC.

STAGE RESULT

1. Jonathan Caicedo (EF Pro Cycling) 04:02:33
2. Giovanni Visconti (Vini Zabu' - Brado-KTM) +00:21
3. Harm Vanhoucke (Lotto Soudal) +00:30

GENERAL CLASSIFICATION

1. Joao Almeida (Deceuninck-Quick-Step) 07:44:25
2. Jonathan Caicedo (EF Pro Cycling) +00:00
3. Pello Blibao (Bahrain-McLaren) +00:37