Briton Tao Geoghegan Hart won his first Grand Tour stage to climb to fourth place overall at the Giro d'Italia.
Several of the main contenders lost time on the 153km route from Base Aerea Rivolto to Piancavallo north of Venice.
Two-time winner Vincenzo Nibali lost over two minutes on the final climb.
Geoghegan Hart, 25, powered past another contender for pink in Sunweb's Wilco Kelderman for the win in the final few metres of the category one summit finish, after the Dutchman's team-mate Jai Hindley had led up the long final climb.
Stage 15 result:
1. Tao Geoghegan Hart (GB/Ineos Grenadiers) 4hrs 58mins 52secs
2. Wilco Kelderman (Ned/Sunweb) +2secs
3. Jai Hindley (Aus/Sunweb) +4secs
4. Joao Almeida (Por/Deceuninck-Quick-Step) +37secs
5. Rafal Majka (Pol/Bora-Hansgrohe) +1min 2secs
6. Patrick Konrad (Aut/Bora-Hansgrohe) +1min 29secs
7. James Knox (GB/Deceuninck-Quick Step) +1min 36secs
8. Pello Bilbao (Spa/Bahrain-McLaren) +1min 36secs
9. Jakob Fuglsang (Den/Astana) +1min 36secs
10. Vincenzo Nibali (Ita/Trek-Segafredo) +1min 36secs.