Bettiol hunted down Frenchman Remi Cavagna of Deceuninck who had escaped from a big breakaway group with 26 kilometres to go and finished 15 seconds ahead of fellow Italian Simone Consonni.

The main peloton, including the overall leader, Colombian Egan Bernal of Ineos, finished 23 minutes and 30 seconds after Bettiol.

The breakaway of 23 riders took shape in the first hour of the race on a large flat stage from Rovareta to Stradella which gave the main contenders a chance to recover before the Giro heads back into the mountains. 

Cavagna, a time trial specialist, burst clear with 26 kilometres to go.
 
But Bettiol chased the Frenchman down through the vineyards of Oltrepo, and Cavagna cracked on final short climb. 

Bettiol rode the last seven kilometres alone for the third victory of his career and his first in Italy. It was also his team's first in this year's Giro. 

The Tuscan also gave the host nation its fifth victory since the start in Turin. 

On Friday, the 166km 19th stage from Abbiategrasso finishes with a tough climb up Alpe Merra but has been rerouted to avoid the climb of the Mount Mottarone, out of respect for the victims of the cable car accident there last Sunday.