Spain's Koldo Fernandez de Larrea was second and Briton Mark Cavendish third.
The Tour of Spain finishes on September 19 in Madrid.
Stage Five - Top Twenty:
1. Tyler Farrar (USA/GRM) 5h03min 36sec
2. Koldo Fernandez (ESP/EUS) at 0:00.
3. Mark Cavendish (GBR/THR) 0:00.
4. Wouter Weylandt (BEL/QST) 0:00.
5. Alessandro Petacchi (ITA/LAM) 0:00.
6. Sebastien Chavanel (FRA/FDJ) 0:00.
7. Robert Forster (GER/MRM) 0:00.
8. Denis Galimzyanov (RUS/KAT) 0:00.
9. Theo Bos (NED/CTT) 0:00.
10. Greg Van Avermaet (BEL/OLO) 0:00.
11. Oscar Freire (ESP/RAB) 0:00.
12. Yauheni Hutarovich (BLR/FDJ) 0:00.
13. Manuel Ortega (ESP/ACA) 0:00.
14. William Bonnet (FRA/BTL) 0:00.
15. Daniele Bennati (ITA/LIQ) 0:00.
16. Gonzalo Rabual (ESP/KGZ) 0:00.
17. Johannes Frhlinger (GER/MRM) 0:00.
18. Manuel Cardoso (POR/FOT) 0:00.
19. Andre Kashechkin (KAZ/LAM) 0:00.
20. Sebastien Hinault (FRA/ALM) 0:00.
Overall Top Twenty:
1. Philippe Gilbert (BEL/OLO) 19h00min 06sec
2. Igor Anton (ESP/EUS) at 0:00.
3. Joaquin Rodriguez (ESP/KAT) 0:10.
4. Vincenzo Nibali (ITA/LIQ) 0:12.
5. Peter Velits (SVK/THR) 0:16.
6. Tejay Van Garderen (USA/THR) 0:29.
7. Xavier Tondo (ESP/CTT) 0:49.
8. Frank Schleck (LUX/SAX) 0:50.
9. Ruben Plaza (ESP/GCE) 0:54.
10. Ezequiel Mosquera Miguez (ESP/KGZ) 0:55.
11. Nicolas Roche (IRL/ALM) 0:58.
12. Marzio Bruseghin (ITA/GCE) 1:01.
13. David Arroyo (ESP/GCE) 1:01.
14. Denis Menchov (RUS/RAB) 1:11.
15. Rigoberto Uran (COL/GCE) 1:19.
16. Tom Danielson (USA/GRM) 1:21.
17. Luis Leon Sanchez (ESP/GCE) 1:24.
18. Vladimir Karpets (RUS/KAT) 1:24.
19. Jean Christophe Praud (FRA/OLO) 1:33.
20. Laurens ten Dam (NED/RAB) 2:08.