Oliver Zaugg shocked the cycling world by taking victory at Il Lombardia after a daring attack paid off in the closing stages.
The Swiss rider (Leopard Trek) stayed in touch with the leaders onto the final climb before pushing clear over the top of the Villa Vergano, holding off a group of five pursuers to take his first professional victory by eight seconds.
Irishman Dan Martin (Garmin-Cervelo) won the sprint for second in Lecco, holding off Joaquim Rodriguez (Katusha) as the monument and the season came to a nail-biting conclusion.
Ivan Basso (Liquigas) and Przemyslaw Niemiec (Lampre) rounded out the top five while pre-race favourite Philippe Gilbert (Omega Pharma-Lotto) had to be content with eighth following a mid-race attack.
The Belgian forced his way into a dangerous move on the descent of the Colma di Sormano, a break which saw fellow escapee Vincenzo Nibali (Liquigas) attempt a daring solo attack.
The 2010 Vuelta a Espana winner broke free on the famous Madonna del Ghisallo climb, opening out a gap of one minute and 24 seconds as he passed the famous church at the summit before being reeled in.
With a number of big names putting their cards on the table early the scene was set for Zaugg to fly in under the radar to take what could be a career-defining victory.
A race that often bears the brunt of the weather, the final October edition of the ‘race of the falling leaves’ took place on a bright autumn day with the riders departing Milan ahead of 241 punishing kilometres.
Six men escaped in the early going, with Claudio Corioni (Acqua & Sapone), Omar Bertazzo (Androni Giocattoli), Andrea Pasqualon (Colnago CSF), Yukiya Arashiro (Europcar), Mikel Astarloza (Euskaltel) and Johan Van Summeren (Garmin-Cervelo) building up a gap of eight and a half minutes as the peloton rolled along.
Liquigas and BMC worked on front to peg back the break, the gap cut significantly as the riders hit the Valcava but continued toing and froing as the escapees stuck to their task.
The remnants of the break finally found themselves swept up following the descent to the foot of the Colma di Sormano, by which time the first significant move of the race had been made.
A dangerous group moved clear on the technical descent, Luca Paolini (Katusha) driving on to instigate a 15-man collective containing Gilbert along with Nibali, Jakob Fuglsang (Leopard Trek) and Giovanni Visconti (Farnese Vini).
In a surprise move Fuglsang and Gilbert pushed on again with 56km to go, forcing their breakaway counterparts to bridge back across ahead of the famous Madonna del Ghisallo climb.
Despite the distance to the finish Nibali was the next to attack, striking out on the climb as his rivals regrouped behind, the Italian holding firm before finally admitting defeat with 16.5km left to race.
A new climb for the 2011 edition, the Villa Vergano was to be the decider with Team Sky keeping the pace high as a depleted group of favourites hit the narrow slopes.
After a big turn from Thomas Löfkvist on the front it was Zaugg who attacked, allowed clear by the bunch only to hold on take his first win on one of the grandest stages of them all.