Spain's Samuel Sanchez won the mountainous fourth stage of the 2010 Tour of Basque Country (Vuelta Ciclista al Pais Vasco 2010) on Thursday as Alejandro Valverde (Caisse d'Epargne) reclaimed the overall lead from Rabobank's Oscar Freire.

Sanchez pulled away during the ascent of the Alto de Uzartza to finish two seconds ahead of compatriot Valverde, who had taken the first two stages of the six-leg race before surrendering the lead to Oscar Freire.

Olympic road race champion Sanchez won the 160-kilometer (99-mile) stage in 4 hours, 5 minutes, 16 seconds.

Team Rabobank's Robert Gesink and Christopher Horner of Team RadioShack crossed the line alongside Valverde and trail the leader by just one second in the overall standings.

Friday's penultimate stage is a 170-kilometer ride from Arrate to Orio that features six mountain climbs.

Friday's stage is a hilly trek from Arrate to Orio. The 2010 Tour of the Basque Country finishes on Saturday with an individual time trial in Orio.

Watch 2010 Tour of the Basque Country video highlights in our Roadcycling.com videos section and watch the Vuelta Ciclista al Pais Vasco 2010 race live online at www.universalsports.com/cycling.