Nairo Quintana (Movistar) put in a late attack from a small group of contenders on the day's final climb to win stage four of the Tour of the Basque Country on Thursday.
Overnight leader Sergio Henao (Sky) placed second at two seconds to retain his leader's jersey, with Alberto Contador (Saxo-Tinkoff) in third.
Henao leads Quintana by just six seconds in the overall classification. Henao's Sky team-mate Richie Porte is third at 10 seconds.
Earlier, Daniele Ratto (Cannondale), Peter Velits (Omega Pharma-QuickStep) and Matteo Montaguti (Ag2r) had hit the final rain-lashed ascent at the end of the race's 'queen' stage with a slim lead over the chasing peloton. Ratto then fell back, leaving Velits and Montaguti clear up front.
Behind, the pace was upped as Movistar hit the front of the bunch. Simon Spilak (Katusha) attacked and swiftly bridged up to the tiring Velits and Montaguti, passing them with ease.
Carlos Betancur (Ag2r) saw his opportunity to try and catch Spilak, perhaps in an attempt to make amends for the previous day's close second-place behind Henao. Porte reacted quickly to Betancur's move, followed by Contador, Quintana and Henao.
Spilak was caught within the final 3km by the elite chase group, as Porte continued to set a steady pace towards the finish. Within the final few hundred metres, Quintana launched a big attack, quickly distancing the rest of the group to take the stage.
Jean-Christophe Peraud (Ag2r) and later Andrew Talansky (Garmin-Sharp) both crashed after the finish line on slick roads. Peraud nearly took out the entire ensemble of photographers.
The climbing continues tomorrow (Friday) with a stage featuring ten categorised climbs from Eibar to Beasain over 166 kilometres. The race concludes with a decisive 24-kilometre time trial on Saturday (April 6) in Beasain. If strong time triallist Porte can stay within striking distance of the lead on Friday, he's a sure bet for the overall win to add to his Paris-Nice title.
Tour of the Basque Country 2013, stage four: Trapagaran to Eibar, 151km
1. Nairo Quintana (Col) Movistar in 3-58-52
2. Sergio Henao (Col) Sky at 2 secs
3. Alberto Contador (Spa) Saxo-Tinkoff
4. Carlos Betancur (Col) Ag2r
5. Simon Spilak (Slo) Katusha
6. Richie Porte (Aus) Sky
7. Jean-Christophe Peraud (Fra) Ag2r at same time
8. Pieter Weening (Ned) Orica-GreenEdge at 16 secs
9. Samuel Sanchez Gonzalez (Spa) Euskaltel-Euskadi at 23 secs
10. Alberto Losada (Spa) Katusha at 24 secs
Overall classification after stage four
1. Sergio Henao (Col) Sky in 16-23-20
2. Nairo Quintana (Col) Movistar at 6 secs
3. Richie Porte (Aus) Sky at 10 secs
4. Alberto Contador (Spa) Saxo-Tinkoff at 10 secs
5. Simon Spilak (Slo) Katusha at 10 secs
6. Carlos Betancur (Col) Ag2r at 21 secs
7. Jean-Christophe Peraud (Fra) Ag2r at 26 secs
8. Pieter Weening (Ned) Orica-GreenEdge at 35 secs
9. Giampaolo Caruso (Ita) Katusha at 35 secs
10. Samuel Sanchez (Spa) Euskaltel-Euskadi at 47 secs
Joe Dombrowski on the front
Nairo Quintana wins the stage
Sergio Henao finishes second
Tour of the Basque Country 2013: Related links
Stage three: Henao takes lead in Tour of Basque Country
Stage two: Gavazzi moves into lead
Tour of the Basque Country stage two photo gallery
Tour of the Basque Country stage one photo gallery
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