The 161 kilometre stage, which began in Florence, presented an ideal opportunity for a breakaway group to enjoy success with a medium mountain profile.

A group of 25 would move away from the peloton early in the stage, which featured four challenging climbs.

Fraile and fellow Spaniard Mikel Landa attacked from the bunch on the second climb and spent much of the day out in front, but the latter would eventually fall away.

France's Pierre Rolland, Portugal's Rui Costa and Tanel Kangert of Estonia would join Fraile at the head of the race as they headed towards its conclusion.

Despite a late burst from Rolland, the quartet would eventually sprint for the stage win, with Fraile winning in a time of 4 hours, 23min and 14sec.

His three breakaway companions would end on the same time, along with a closing group of five riders who nearly caught the breakaway.

"It's been an incredible day," said Fraile, after the Dimension Data rider earned his first Grand Tour stage win.

"It couldn't have gone any better, I'm super happy.

"It's a win I've dreamt of for a long time.

"I've had a passion for the Giro since I was a kid.

"This is my best win ever."

The Netherlands' Tom Dumoulin maintained his 2:23 lead over second place Nairo Quintana of Colombia in the overall standings, after his team helped him fend off attacks today.

Dumoulin would finish in a group containing the majority of general classification contenders.

Fellow Dutch rider Bauke Mollema remains 2:38 behind in third place, with France's Thibaut Pinot a further two seconds back.

Defending champion Vincenzo Nibali of Italy is 2:47 off the lead.

The Tour of California, another International Cycling Union (UCI) WorldTour race, held its fourth stage today.

Evan Huffman led a one-two for American team Rally Cycling. 

Huffman crossed the line in 3:41:52 with teammate Rob Britton finishing second, while The Netherlands' Lennard Hofstede took third.

Poland's Rafal Majka remains in the race lead, with New Zealand’s George Bennett two seconds behind.