(Reuters) - Simon Yates' slender lead in the Vuelta a Espana was cut from 33 to 25 seconds after the Briton lost ground to Spaniard Alejandro Valverde in Wednesday's mountain stage, which was won by Canadian rider Michael Woods.
Woods snatched a first grand tour victory by edging ahead of Belgian Dylan Teuns in thick mist 400 metres from the summit finish of the Balcon de Bizkaia mountain at the end of the 157km stage from Getxo, outlasting a breakaway also containing Team Sky's David de la Cruz and Rafal Majka.
Teuns finished five seconds behind Woods while Spaniard De La Cruz finished third, 10 back.
Yates, bidding to become the second consecutive Briton to win the Vuelta after Chris Froome's victory last year, finished two minutes 48 seconds behind Woods in 17th place, third fastest of the general classification hopefuls, losing eight seconds to Spaniards Valverde and Enric Mas.
Nairo Quintana's hopes of a repeat of his 2016 Vuelta victory faded further as the Colombian finished three minutes 44 seconds behind Woods, sliding down to sixth place overall, two minutes 11 seconds off Yates.
Dutchman Steven Kruijswijk had climbed into third the day before following a successful time trial but he fell back to fifth place after a disappointing performance in the mountains, with Spaniard Mas taking his spot in third, one minute 22 seconds behind Yates.
Thursday sees the final flat stage of the Vuelta, a 186.1km route from Ejea de los Caballeros to Lleida before two final summit finishes in the Pyrenees mountains, which will almost certainly determine the winner of the race, which culminates with Sunday's procession through Madrid.
(Reporting by Richard Martin; Editing by Toby Davis)