Peter Sagan turned around an annus horribilis in style on Sunday, celebrating his third straight road race world title less than three months after being kicked out of the Tour de France.

The Slovakian outsprinted local favourite Alexander Kristoff and Australian Michael Matthews, who were second and third respectively, after staying quiet all day in the main pack.

"Every time something bad happens, it is for something good. You have to see it the optimistic way," the 27-year-old Sagan told a news conference.

Sagan was disqualified from the Tour on July 4 after he sent Briton Mark Cavendish crashing in the final sprint of the fourth stage.

Sagan, one of the most colourful characters in the peloton, took time off, resuming at the Tour of Poland in late July but skipping the Vuelta, often regarded as an excellent warm-up race for the world championships.

"I had a lot of fun, I had a lot of time to spend time with my family, it was good," said Sagan.

He came into Sunday's 267.5-km race with fresh legs and a fresh mind, admitting he had 'no strategy'.

"You have the feeling he has no interest in the race, he's joking, screaming around and acting the fool at the back of the bunch and, in the end, he wins," said France's Anthony Roux.

Ten kilometres from the finish, on the last climb of Salmon Hill -- a 1.4-km ascent at an average gradient of 6.4 percent -- the Slovakian thought he had no chance to win.