Peter Sagan won his third world title in a row in a dramatic finish to the men's road race at the World Championships in Norway, while Dan Martin was the best-placed of the Irish riders - two months after being diagnosed with a broken back.

The Slovakian had barely featured among the lead riders throughout the 267.5-kilometre race in Bergen.

He was classified 80th approaching the final climb up Salmon Hill, but timed his ride to perfection.

Sagan held off Norwegian Alexander Kristoff in a sprint finish to become the first man to win three consecutive world crowns.

Martin came home in 26th, seven places ahead of his cousin Nicolas Roche. Ryan Mullen was 126th with Conor Dunne and Sean McKenna at the tail end of the peloton.

Martin was surprised to finish so strongly. "Just to get to the start line is an achievement today - I was diagnosed with a broken back eight weeks ago," he said.

"It’s been a really hard, long season. I hoped to finish today, so to be in the front group is a big surprise.

"That was a great performance from the team today. Sean and Conor were in the break, and did a great job flying the flag out there. Conor put me in position for when it really started to get hard in the race too."

McKenna and Dunne attacked at the start, building a gap of over seven minutes on the road. The two Irishmen were in a group of seven riders and kept their lead for over 180km, when the main peloton pushed hard on the 17.8km circuit.

This was the first Elite World Championships for McKenna, and the significance of his effort was not lost the Dubliner.

"This was one of the best days I’ve ever had on the bike; I was willing to do anything in the break," he said.

"My dad was on the cobbled climb and every time I passed I saw him smile. You’ve no idea how many races he brought me to and I was last in every single one, and I was just in the break in the World Championships - that’s unbelievable!"

Frenchman Tony Gallopin attempted to break clear 13km from home, but he was swallowed up at the foot of Salmon Hill.

At the same time a crash accounted for several riders, before Italian Gianni Moscon and France's Julian Alaphilippe used the final climb to steal a march on the peloton.

With 4.3km left Alaphilippe made what appeared to be a decisive burst, but he was eventually chased down.

Sagan and Kristoff forced themselves to the head of the pack and crossed the finish line together with the 27-year-old winning by a hair's breadth.

"It was not easy, guys were changing in the front all the time," Sagan told the BBC.

"I tried to go with the breakaway and it came down to a sprint, it was unbelievable.

"Kristoff was racing at home so I'm sorry, but of course I'm happy to win.

"(Three in a row) is something special for sure. For me it's something very nice."

Australian Michael Matthews took third place with Italian Matteo Trentin fourth and a surprise fifth place for Britain's Ben Swift.

The 29-year-old from Rotherham said: "Sagan was incredible, I think all of us were trying a couple of moves because it was all over the place, but he did amazing.

"The team was brilliant today, we set out what we wanted to do and everyone rode brilliantly."