FORLI, Italy (AP) Alberto Contador held on to the overall lead and gained time on rival Richie Porte in the almost entirely flat 10th stage of the Giro d'Italia on Tuesday.
Italian rider Nicola Boem won the stage after getting into an early breakaway that reached the finish.
Porte had to change a punctured tire and dropped behind the main pack in the final kilometers, losing 47 seconds to the general classification leaders. A few members of Porte's Sky team escorted him to the finish in a frantic effort to avoid more lost time.
Porte dropped from third to fourth overall, 1:09 behind Contador.
''It certainly wasn't an easy day,'' Contador said. ''There can be surprises every day at the Giro. The other day it was my fall. Today it was Richie who was unlucky. ... But he didn't lose that much time.''
Contador dislocated his shoulder in a fall on the final sprint of Stage 6.
''I still feel pain, but it's healing,'' said the Spaniard, who rides for the Tinkoff-Saxo team.
A two-time Tour champion, Contador won the Giro in 2008 and was also triumphant in Milan in 2011 but was stripped of that title for testing positive in the 2010 Tour.
Fabio Aru, an Italian with Astana, is second overall, three seconds behind Contador, and Mikel Landa, a Spaniard with Astana, is third, 46 seconds back.
Boem required nearly 4 1/2 hours over the 200-kilometer (124-mile) leg from Civitanova Marche to Forli, along the Adriatic coast.
Stage 11 on Wednesday is a hilly 153-kilometer (95-mile) leg from Forli to Imola, ending on the Enzo and Dino Ferrari racing car circuit that formerly hosted the San Marino Grand Prix.
The 98th Giro ends on May 31 in Milan.