Scarponi won the 18th stage but the overall lead is still held by Menchov
Italian Michele Scarponi won the 18th stage of the Giro d'Italia from Sulmona to Benevento on Thursday.
The Serramenti rider, 29, came home in a time of four hours, seven minutes and 41 seconds.
Russian Denis Menchov of Rabobank finished safely in the peloton - almost four minutes behind - to maintain his overall lead.
Menchov leads Italian 2007 champion Danilo Di Luca by 26 seconds ahead of Friday's uphill stage.
Liquigas rider Franco Pellizotti is two minutes behind Menchov in third and 2006 winner Ivan Basso is fourth.
Last year's Tour de France winner Carlos Sastre lies just behind Basso in fifth while American Lance Armstrong, gaining fitness for a tilt at an eighth Tour de France title in July after coming out of retirement, is in a creditable 12th position overall.
Friday's 19th stage is a 164-kilometre (102-mile) leg from Avellino to Mount Vesuvius, and is the race's final uphill finish.
Scarponi, 29, finished ahead of Colombian Felix Cardenas of Barloworld on Thursday with American Danny Pate of Garmin in third.
Stage 18 results (Thursday):
1. Michele Scarponi (Italy / Diquigiovanni) 4 hrs 7 mins 41 secs
2. Felix Cardenas (Colombia / Barloworld) same time
3. Lars Bak (Denmark / Saxo Bank) same time
4. Danny Pate (U.S. / Garmin) same time
5. Dmytro Grabovskyy (Ukraine / Team ISD) +6
6. Dries Devenyns (Belgium / Quick-Step) +20
7. Jason McCartney (U.S. / Saxo Bank) +24
8. Giovanni Visconti (Italy / Team ISD) +37
1. Denis Menchov (Russia / Rabobank)
2. Danilo Di Luca (Italy / Team LPR) +26 sec
3. Franco Pellizotti (Italy / Liquigas) +2:00
4. Ivan Basso (Italy / Liquigas) +3:28
5. Carlos Sastre (Spain / Cervelo) +3:30
6. Levi Leipheimer (U.S. / Astana) +4:32
7. Michael Rogers (Australia / Columbia) +7:05
8. Stefano Garzelli (Italy / Acqua & Sapone) +8:03