Pablo Castrillo escaped from a breakaway and held off his pursuers on the climb to the line for an emotional Vuelta a España stage win on Thursday as Ben O'Connor protected his overall lead.

Castrillo, a Spaniard who rides for Kern Pharma, attacked at just before the 10-kilometre climb to the finish of stage 12.

The 23-year-old celebrated his first World Tour victory, and the first by a Spaniard on this year's Vuelta, by crossing the line pointing skywards.

He dedicated his success to his team's founder and former president Manolo Azcona, who died during the night at the age of 71.

"I thought about Manolo the whole stage. I had his strength by my side in those last few kilometres," said Castrillo.

"I suffered a lot but to be able to win a stage in the Vuelta is just crazy," he added. "I don't have any words. I've gone to the end of my strength."

Castrillo finished eight seconds ahead of Max Poole after the other members of the elite escape group stopped chasing to avoid helping each other.

Poole, a 21-year-old Briton, had been part of the breakaway the previous day when he finished third.

O'Connor, an Australian who rides for AG2R-Decathlon maintained his 3min 16sec lead over the Slovenian from Red Bull.

The pack finished 6min 29sec behind Castrillo on a hilly 125.7 kilometre meander through Galicia from Ourense to the Manzaneda ski resort. (AFP)