Britain's Bradley Wiggins has retained the overall lead in the Vuelta a Espana after completing the 12th stage.
The Team Sky rider, who took over the red jersey on Wednesday, is competing in his first event since sustaining a broken collarbone at the Tour de France in July.
Peter Sagan of Slovakia won the 167.3km stage from Ponteareas to Pontevedra to secure his second win of the tour.
German rider John Degenkolb and Italy's Daniele Bennati completed the podium.
Wiggins, who is using the Vuelta to prepare for the time-trial at the road World Championships which takes place in Copenhagen on 21 September, holds a seven-second lead over team-mate Christopher Froome and nine seconds ahead of Sweden's Fredrik Kessiakof of Astana.
"It was a sprint day, but it was still really hard, not flat by any means," Wiggins said.
"I stayed close to the front which probably isn't where you'd expend the least energy but it's certainly the safest.
"I just tried to stay out of trouble, I still get a bit nervous in those sorts of situations.
"We're in a good position, I'm just trying not to get too carried away with it all."
The 'Tour of Spain' finishes on 11 September in Madrid.
The event continues on Friday with a 158.2-km run from Sarria to Ponferrada which includes three mountain passes.
Result and overall standings after the 167.3km 12th stage of the Tour of Spain from Ponteareas to Pontevedra:
1. Peter Sagan (Slovakia / Liquigas) 4 hrs 03 mins 01secs
2. John Degenkolb (Germany / HTC - Highroad) same time
3. Daniele Bennati (Italy / Leopard)
4. Alessandro Petacchi (Italy / Lampre)
5. Juan Jose Haedo (Argentina / Saxo Bank)
6. Tom Boonen (Belgium / Quick-Step)
7. Greg Van Avermaet (Belgium / BMC Racing)
8. Paul Martens (Germany / Rabobank)
9. Nikolas Maes (Belgium / Quick-Step)
10. Lloyd Mondory (France / AG2R)
1. Bradley Wiggins (Britain / Team Sky) 46hrs 53mins 47secs
2. Chris Froome (Britain / Team Sky) +7"
3. Fredrik Kessiakoff (Sweden / Astana) +9"
4. Vincenzo Nibali (Italy / Liquigas) +10"
5. Jakob Fuglsang (Denmark / Leopard) +19"
6. Bauke Mollema (Netherlands / Rabobank) +36"
7. Maxime Monfort (Belgium / Leopard) +1:06"
8. Juan Jose Cobo (Spain / Geox) +1:27"
9. Haimar Zubeldia (Spain / RadioShack) +1:53"
10. Janez Brajkovic (Slovenia / RadioShack) +2:00"