Britain's Steve Cummings secured "the best win of his career" as he took stage 13 of the Vuelta a Espana, while Spaniard Joaquin Rodriguez retained the overall lead.
BMC rider Cummings powered away from the breakaway group with one kilometre left to cross the line unchallenged.
Australia's Cameron Meyer took second with Spain's Juan Antonio Flecha third.
Rodriguez retains a 13-second lead over Alberto Contador, with Britain's Chris Froome still 51 seconds back in third.
Cummings, 31, has crashed four times this season, breaking his pelvis during the Tour of the Algarve in February and his left wrist while racing in the Vuelta al Pais Vasco in April.
He said: "It's been a long, hard year. I crashed really badly in the Tour de France so I wasn't sure of my condition when I came here.
"But I knew if I got through the first week all right, things could start to get better."
The 31-year-old, who was also involved in an accident during the Tour of California, was the only Briton in the Tour de France not to win a stage.
But he now joins Froome, Mark Cavendish, David Millar and Bradley Wiggins as British Grand Tour stage winners in 2012.
"When I was a kid I always watched the Giro d'Italia, Tour and Vuelta and dreamed of taking a stage in one of them," he added.
"But opportunities are very limited, particularly if you're working for a team leader. I don't feel I've reached my top condition yet."
Froome's Team Sky team-mate Ben Swift finished ninth.
Saturday's stage 14 is a 149.2km (92.7-mile) race through the mountains from Palas de Rei to Puerto de Ancares.
Stage 13 results:
1. Steven Cummings (Britain/BMC Racing) 4:05:02"
2. Cameron Meyer (Australia/Orica) +4"
3. Juan Antonio Flecha (Spain/Team Sky)
4. Simon Clarke (Australia/Orica) +14"
5. Linus Gerdemann (Germany/RadioShack)
General classification after 13 stages:
1. Joaquin Rodriguez (Spain/ Katusha) 48:56:17"
2. Alberto Contador (Spain/ Saxo Bank) +13"
3. Chris Froome (Britain/ Team Sky) +51"
4. Alejandro Valverde (Spain/ Movistar) +1:20"
5. Robert Gesink (Netherlands/ Rabobank) +2:59"