Arnaud Demare picked up his second stage victory of this year's Giro d'Italia as he blew by his sprint rivals in Matera.

The short, sharp climb in the final kilometres of the 188km stage six from Castrovillari made the likes of Peter Sagan and Michael Matthews the favourites to take victory and they were to the fore as the reduced peloton passed under the flamme rouge.

Demare was well down at that point, taking the penultimate corner in around 20th place, but the French national champion came out of the final left-hander with a burst of speed and powered his way past to take a comfortable victory ahead of Matthews.

"It was a really tough climb, really steep," said Demare, who also won stage four in Villafranca Tirrena. "I lost a few positions but I didn't go crazy. I managed to get back on in the wheels and just kept following.

"I launched the sprint and can't believe I got to the finish. It was really hard.

"This morning I wasn't even sure it was a chance for a sprint so it's amazing. I said if I won a first one there would be a chance for more."

There was no change at the top of the general classification, in which Deceuninck-QuickStep's Portuguese rider Joao Almeida leads by 43 seconds from Pello Bilbao of Bahrain-Merida.

That was despite a moment of drama for Almeida around 36km from home when he stopped by the side of the road, apparently to swap a broken radio, but was struck from behind by UAE Team Emirates rider Brandon McNulty who noticed him too late.

Almeida was forced over by the impact but did not look troubled as he resumed his race.

"I stopped because I had a radio problem," he said. "I didn't crash, I was just changing the radio but then one rider hit me in the back so I ended up crashing anyway.

"But I'm OK, I think."

Two-time Giro winner Vincenzo Nibali remains fifth, 61 seconds down, four seconds ahead of NTT Pro Cycling's Domenico Pozzovivo, with Jakob Fuglsang and Steven Kruijswijk in seventh and eighth place respectively.