'Purito' attacked in the final part of the Salita di Ello, a 3.25 kilometer ascent at an average gradient of 7.4 percent, and held off a strong chasing group on the flat.

The win gave Rodriguez top spot in the WorldTour standings ahead of Great Britain’s Tour de France champion Bradley Wiggins.

Spain’s Samuel Sanchez of Euskaltel-Euskadi was second and Colombian Rigoberto Uran of Team Sky Procycling finished third.

"This is the most important triumph of my whole career," Rodriguez commented after being celebrated on the podium.

"For me it was a perfect season. I won Fleche Wallonne, I finished 2nd in the Giro d'Italia and third in Vuelta a Espana. After that I did my best in order to get ready for the World Championships and Giro di Lombardia. In the former my performance was so-so, but in the latter it was a triumph."

"Today I was feeling in great shape, so I made my teammates work during all the crucial moments of the race. When I saw that all my rivals were tired and I felt so great, I realized I had a great chance to win. To tell the truth I thought that somebody could join me in that attack, but instead nobody could answer and that makes this victory even greater."

As expected, the brutal climb to the Muro di Sormano sorted the men from the boys.

The two-kilometer ascent at an average gradient of some 15 percent blew the peloton apart with Alberto Contador (Team Saxo Bank-Tinkoff Bank), Vincenzo Nibali (Team Liquigas-Cannondale) and Rodriguez among those setting the pace in front.

Team BMC Racing's newly crowned World champion Philippe Gilbert crashed in the descent with about 70 kilometers to go and pulled out.

“He’s got some burns and cuts but nothing serious,” BMC team manager John Lelangue told RAI.

Team BMC Racing's Dr. Max Testa later confirmed Gilbert has superficial abrasions on his right elbow, right shoulder and right knee, but no major muscle problems, no broken bones and no concussion. "Right now it just looks he just has some bad road rash," Testa said.

Gilbert later explained he had just regained contact with the front group when he crashed while going 60 kilometers an hour.

"With the cold, I was feeling a bit paralyzed and, at the beginning, I was afraid because I couldn't move for one or two minutes and I was fearing there was something broken," Gilbert explained.

"Then I checked and saw everything was OK. So in the end it's a pity because I had good feelings and could have maybe done something. But I'm feeling lucky I crashed now and not one week ago. If it had been a stage race, I think I wouldn't have abandoned. But today, after the crash, my race was over."

Nibali also hit the deck in the descent from the Madonna del Ghisallo but he managed to get back on the bike and rejoin the peloton.

However, the Italian - one of the pre-race favorites with Contador, Rodriguez and Gilbert - had not fully recovered before the last ascent and could not be a factor in the finale.

Watch video highlights from the 2012 Giro di Lombardia and the World Championships in our videos section after the race (U.S.-only due to geo broadcast rights restrictions). Spread the word to friends and fellow cycling fans.