Sweden's Frederik Kessiakoff won the 11th stage of the Tour of Spain on Wednesday, a 39km individual time trial from Cambados to Pontevedra in Galicia.
Spaniard Joaquim Rodriguez, of the Katusha team, has just a fingernail's grip on the overall leader's red jersey, however.
He lies one second ahead of compatriot and 2008 Vuelta champ Alberto Contador, back from a two-year drugs ban, and 16 seconds over Britain's Chris Froome, runner up at this year's Tour de France.
The 32-year-old Kessiakoff of Team Astana stamped his authority on the time trial with an impressive 52 min 32 sec, beating Saxo Bank's Contador by 17 seconds and Froome of Team Sky by 39 seconds.
It is the Swede's first stage win in a major tour, though he had fired a warning shot in the 2012 Tour of Switzerland by winning an individual time trial there, too.
Among the favourites, Contador gained the most ground in the time trial, seemingly at ease as he took advantage of a third-category climb of about 10km up Monte Castrove.
The Catalan climber clawed back 22 seconds on Froome, but could not reach Rodriguez.
On Thursday the riders face a spectacular 190km coastal route through Galicia from Vilagarcia de Arousa to Mirador de Ezaro, a third category mountain pass with inclinations of over 13 per cent.