5 April 2010 – Zierbena to Zierbena, 152 km (94 mi)
Alejandro Valverde was awarded the opening stage after Óscar Freire, who crossed the line first, was disqualified for interfering with him in the sprint. After the subsequent removal of Valverde's results, Freire was reinstated as stage winner. Pre-race favourite, Samuel Sánchez missed a decisive split in the peloton and finished 1:38 behind the peloton, making a victory for him seem very unlikely.
The victory put Alejandro Valverde only one second ahead of Chris Horner and Robert Gesink respectively. The overall favourites knew they had to wait for the Alto de Usartza, that ended just two kilometres from the finish.
A large attack group including mountains classification leader Amets Txurruka spent much of the day ahead of the peloton. On the penultimate climb Txurruka attacked solo, but crashed on the descent towards the final climb. He was able to complete the stage, but broke his collarbone in the incident and had to drop out before the final time trial.
Robert Gesink who was in 3rd place after the previous stage, is now in 8th place after experiencing a crash on the final climb. His team (Rabobank) reported that he may have broken a bone in his hand.
Joaquim Rodríguez had attacked out of the chasing peloton with about 20 km to go, passing the remnants of an earlier escape group. He had come into the stage 48 seconds down on the general ranking, dangerous enough for Valverde, Horner and Sánchez to give chase.
Joaquim Rodríguez was happy with the result and the ITT is different than normal because it has a hilly finish. His dream is to take the GC.