Colombian rider Ivan Parra picked up only the third win of his career on an arduous stage 13 of the Giro d'Italia.
Parra managed to hold off his challengers in the mountains
But overnight leader Ivan Basso conceded the leader's pink jersey after a tough day in the saddle.
The Italian, who finished third to Lance Armstrong in last year's Tour de France, dropped to second behind Armstrong's team-mate Paolo Savoldelli.
Savoldelli pulled clear of his countryman in the final few kilometres and now leads overall by 50 seconds.
Basso finished 68 seconds behind Savoldelli and slipped to second place in the overall standings.
"I had stomach pains from the start of the stage and it was
difficult to eat because I felt sick," said Basso.
"To be honest the time I lost isn't that much considering I felt so bad."
Bjarne Riis, team director of Basso's CSC team, said:
"Fortunately the team rode well all day, so we limited our
losses. I think we can say we've been lucky."
CSC media officer Brian Nygaard said Basso would start
Sunday's 210-km mountain stage from Egan to Livigno but was unsure how he would perform.
"Ivan managed to eat normally after the stage and his
digestive system is back to normal but he has obviously suffered a lot," Nygaard said.
"It could be difficult for Ivan tomorrow after the effort he
made but he will definitely start the stage."
Saturday's stage saw a host of big-name withdrawals, with 2000 Giro winner Stefano Garzelli pulling out because of injuries from an earlier fall.
The sprint quartet of Robbie McEwen, Stuart O'Grady, Baden Cooke and Jaan Kirsipuu also withdrew to save their legs for July's Tour de France.
Giro d'Italia stage 13 results:
1 Ivan Parra (Col) Selle Italia-Colombia 6.31.35
2 Juan Manuel Garate (Spa) Saunier Duval-Prodir +23 seconds
3 Jose' Rujano Guillen (Ven) Selle Italia-Colombia +23
4 Pietro Caucchioli (Ita) Credit Agricole +27
5 Tadej Valjavec (Slo) Phonak Hearing Systems +1:45
6 Matthias Kessler (Ger) T-Mobile Team +2:55
7 Giampaolo Caruso (Ita) Liberty Seguros-Wurth Team +3:03
8 Wladimir Belli (Ita) Domina Vacanze +3:48
9 Paolo Savoldelli (Ita) Discovery Channel +4;00
10 Gilberto Simoni (Ita) Lampre-Caffita +4:06
1 Paolo Savoldelli (Ita) Discovery Channel 60.31.12
2 Ivan Basso (Ita) Team CSC +50s
3 Danilo Di Luca (Ita) Liquigas-Bianchi +53
4 Gilberto Simoni (Ita) Lampre-Caffita +2:16
5 Juan Manuel Garate (Spa) Saunier Duval-Prodir +2:39
6 Pietro Caucchioli (Ita) Credit Agricole +3:25
7 Serguei Gonchar (Ukr) Domina Vacanze +4:05
8 Jose' Rujano Guillen (Ven) Selle Italia-Colombia +4:23
9 Marzio Bruseghin (Ita) Fassa Bortolo +4.54
10 Dario David Cioni (Ita) Liquigas-Bianchi +4:54