Farnese Vini-Selle Italia’s Andrea Guardini of Italy celebrates as he crosses the finish line to win the 149-km Stage 18 of the Giro d’Italia from San Vito di Cadore to Vedelago, May 24, 2012. (REUTERS/Alessandro Garofalo)

By Alasdair Fotheringham

VEDELAGO, Italy , May 24 (Reuters) – Up-and-coming Italian Andrea Guardini inflicted a surprise defeat on world champion Mark Cavendish in a bunch sprint at the end of Stage 18 of the Giro d’Italia on Thursday.

Spain’s Joaquim Rodríguez retained the overall lead with three days remaining.

Cavendish hammered his handlebars in frustration after the 22-year-old Farnese Vini rider outpowered the Briton by more than a bike length on the flat stage from San Vito di Cadore to Vedelago. Italy’s Roberto Ferrari was third.

“I couldn’t be happier, it’s an amazing thing because I’ve beaten the world champion, at least today,” Guardini, in his second year as a professional, told reporters.

“I accelerated away with 250 metres to go, I saw Cavendish was behind me and couldn’t beat me, it’s incredible.”

Guardini is riding in his first major Tour.

“Just making it through to the third week of the Tour was already a little victory for me,” he said.

“And after a victory like this one, I’m going to do my best to go all the way through to Milan.

Cavendish was honest in defeat.

“He was the fastest in a fast sprint today and certainly had more energy than me,” he told Italian television reporters.

Asked why he had thumped his handlebars, he answered simply; “I don’t like losing.”

Leading the points competition, Cavendish said he had made a big effort to increase his lead by winning a mid-stage bonus sprint at the top of a climb.

“I used up some energy there, but I want to take the red jersey (of points competition leader) all the way to Milan.”

“If it wasn’t for that crash with [Italian sprinter Roberto] Ferrari (on stage three), I think I’d be in a comfortable position now for the red jersey, but now I’ll have to fight for it.”

Overall, as the race tackles the first of two key mountain stages on Friday, Spain’s Rodríguez remains in the overall lead, 30 seconds ahead of Canada’s Ryder Hesjedal and with a one minute 22 second advantage over former double Giro winner Ivan Basso of Italy.

“Hesjedal is not wearing pink (of leader’s jersey) but he’s the clear overall favourite,” Rodríguez told reporters.

“I have to try and drop him before Sunday’s time trial, and the same goes for everybody else if they want to win.”

The Giro finishes on Sunday in Milan with an individual time trial.