Valverde also won the Tour of the Basque Country in April

The Kelme rider won a sprint finish after a group of about 10 riders broke away from the main peloton towards the end of the leg from Burgos to Soria.

Australian Stuart O'Grady was second, several bike lengths behind, with Russian Denis Menchov third.

Benoit Joachim of Luxembourg secured the overall lead from US Postal team-mate Max van Heeswijk thanks to seconds won in intermediate sprints.

Stage results:

1. Alejandro Valverde, Spain, Kelme, 3 hours, 43 minutes, 17 seconds.
2. Stuart O'Grady, Australia, Cofidis, same time.
3.Denis Menchov, Russia, Illes Balears-Banesto, st.
4. Oscar Freire, Rabobank, st.
5. Roberto Heras, Liberty Seguros, st.
6. Stefano Garzelli, Italy, Vini Caldirola, st.
7. Francisco Mancebo, Spain, Illes Balears-Banesto, st.
8. Aitor Gonzalez, Spain, Fassa Bartolo, st.
9. Damiano Cunego, Italy, Saeco, st.
10. Cadel Evans, Australia, T-Mobile, st.

Overall standings:

1. Benoit Joachim, Luxembourg, US Postal, 9:16:00.
2. Max Van Heeswijk, Netherlands, US Postal Service, 16 seconds behind.
3.Floyd Landis, US, US Postal, 22 seconds behind.
4. Michael Barry, Canada, US Postal, st.
5. Manuel Beltran, Spain, US Postal, st.
6. Victor Hugo Pena, Colombia, US Postal, st.
7. David Zabriskie, United States, US Postal, st.
8. Alexandre Vinokourov, Kazakhstan, T-Mobile, 38 seconds.
9. Cadel Evans, Australia, T-Mobile, st.
10. Alejandro Valverde, Spain, Kelme, 45 seconds.