Switzerland's Oliver Zaugg claimed the Tour of Lombardy classic when he powered away in the final climb to snatch his maiden individual win as a professional on Saturday.
The Leopard-Trek rider took off with about 10 km left in the demanding ascent to the Salita di Ello and kept a chasing group at bay, winning by eight seconds.
Irishman Daniel Martin was second for the Garmin-Cervelo team with Joaquin Rodriguez of Spain (Katusha) coming home third.
World number one Philippe Gilbert failed in his bid to win the 241-km race for the third time in a row, finishing 15 seconds behind the winner.
Belgium's Gilbert, who won the Liege-Bastogne-Liege, Fleche Wallonne, Clasica San Sebastian and Amstel Gold Race classics in awesome fashion, was powerless when Zaugg produced his effort.
It had briefly looked as if Italian Vincenzo Nibali would take the day's laurels when he powered away in the climb to the Madonna del Ghisallo with 52 km left.
The Liquigas rider cracked 17 km from the finish after Team Sky, working for Rigoberto Uran, increased the pace in the chasing pack.
Colombian Uran could not follow when Italian Ivan Basso then turned up the heat, but his effort was not enough to shake off Zaugg, who caught everyone off-guard with his well-timed attack.
Zaugg, 30, is one of the riders set to be kept by manager Johan Bruyneel when Leopard-Trek and Radioshack merge into the Radioshack-Nissan team for the 2012 season.
Provisional result of the 241km Tour of Lombardy from Milan to Lecco on Saturday.
1. Oliver Zaugg (Switzerland / Leopard) 6hrs 20mins 02secs
2. Daniel Martin (Ireland / Garmin) +8"
3. Joaquin Rodriguez (Spain / Katusha)
4. Ivan Basso (Italy / Liquigas)
5. Przemyslaw Niemiec (Poland / Lampre)
6. Domenico Pozzovivo (Italy / Colnago - CSF)
7. Giovanni Visconti (Italy / Farnese Vini) +15"
8. Philippe Gilbert (Belgium / Omega Pharma - Lotto)
9. Carlos Betancour (Colombia / Acqua & Sapone) 10. Riccardo Chiarini (Italy / Androni Giocattoli)