Alfacar - American rider Ben King sprinted away from breakaway partner Nikita Stanlov to win the fourth stage of the Vuelta a Espana on Tuesday as Michal Kwiatkowski hung onto the overall lead.

King of Dimension Data and Kazakh rider Stanlov of Astana were part of an early nine-man breakaway which built a gap of almost 10 minutes as Kwiatkowski's Sky team set a gentle pace in the peloton.

By the first summit finish of this year's race, a category one climb to Alfacar, King and Stanlov were alone. The American surged away with a frantic 100-metre sprint to win the 161.4-kilometre stage starting in Velez-Malaga by two seconds.

"It was a dream come true. For me personally, I'm still in shock," the 29-year-old King told Eurosport immediately after his first stage victory in a major tour. "That was an objective at the start of the year."

French climber Pierre Rolland (EF-Education First) was third, 13 seconds back.

On the final climb, Briton Simon Yates of Mitchelton and German Emanuel Buchmann of Bora-Handsgrohe broke away from the main pack to cut 25 seconds out of Kwiatkowski's lead.

The Pole leads Buchmann by seven seconds, Yates by 10 and Spaniard Alejandro Valverde of Movistar by 13.

"It was a last very demanding climb," said Kwiatkowski, adding that he was happy to keep the red jersey "one more day."

"I'm not the big favourite to win the Vuelta, there's Nairo Quintana, Alejandro Valverde, George Bennett, Simon Yates, Emanuel Buchmann," the Pole said.

"These guys set a very high tempo and in the end we did not come out of it too badly. Despite the multiple attacks, I followed my own rhythm."

The first climbing stage might have put paid to the chances of the men who finished on last year's podium with winner Chris Froome, who is not taking part this year.

Russian Ilnur Zakarin (Katusha) finished 8min 11sec behind King while the 2017 runner up Italian Vincenzo Nibali (Bahrain Merida) was 11min 04sec back.

"With such high temperatures, we'd expect to see a lot of riders suffer," Kwiatkowski said.

Wednesday's fifth stage is a 188.7km run mostly along the Mediterranean coast from Grenada to Roquetas de Mar with one category 2 to potentially break up the peloton and prevent a sprint finish.