Frenchman Tony Gallopin used a late break to win stage seven of La Vuelta as Rudy Molard retained the leader's red jersey.
Gallopin attacked from the leading group with a little over two kilometres of the 185.5km stage from Puerto Lumbreras to Pozo Alcon remaining, and the AG2R La Mondiale rider had enough in reserve to stay away.
World champion Peter Sagan won the sprint for second place, five seconds behind Gallopin.
BMC's Nicolas Roche was in the bunch behind Sagan but UAE Team Emirates' Dan Martin finished 4 minutes and 27 seconds down on the leader after a late puncture.
Groupama-FDJ's Molard saw his overall lead grow as Team Sky's Michal Kwiatkowski lost 25 seconds on the other general classification favourites after crashing on a dusty corner inside the final 10 kilometres of the rolling stage.
Frenchman Molard now leads by 47 seconds from Movistar's veteran Spaniard Alejandro Valverde, who finished third on the stage.
Bora-Hansgrohe's Emanuel Buchmann is a further second back in third overall, with Britain's Simon Yates of Mitchelton-Scott in fourth place, 51 seconds off red.
Kwiatkowski slips to sixth, 66 seconds down as Gallopin's win and bonus seconds move him into fifth place.
Roche is 24th overall, 5:07 off the lead, while Martin is 64th and just under 25 minutes off the pace.
"When we came on the last straight road, I had a plan that if I have a possibility I try to attack," Gallopin said. "I found a good moment - and I'm so happy.
"I looked back just before the last corner, maybe 200m, 300m to go and I saw nobody behind me. So I turned and I went full the last straight - I looked back in the final 50m and they were quite far, so I knew that I can win. So it's fantastic."
La Vuelta continues on Saturday with a fairly flat 195km stage from Linares to Almaden.