Onati - Joaquin Rodriguez edged Samuel Sanchez to win the fifth stage of the Tour of the Basque Country, maintaining his overall advantage over his fellow Spanish cyclist with one stage remaining.
Rodriguez, of the Movistar team, edged Sanchez in a sprint finish to close the 183km stage in 4 hours, 27 minutes, 16 seconds.
Rodriguez remains nine seconds ahead of the Olympic champion before Saturday's 18.9km time trial.
Robert Kiserlovski of Croatia finished two seconds behind in third, while Vasili Kiryienka of Belarus and Lars Petter Nordhaug of Norway trailed by five seconds to round out the top-five.
Saturday's last stage will likely decide which Spaniard wins the 52nd edition with Kiserlovski 26 seconds behind Rodriguez.
Results from the fifth stage of Tour of the Basque Country, a 183km ride from Vera de Bidasoa to Onate on Friday:
Joaquin Rodriguez (ESP/KAT) 4h 27min 16sec, 2. Samuel Sanchez (ESP/EUS)
at 0:00, 3. Robert Kiserlovski (CRO/AST) 0:00, 4. Vasil Kiryienka
(BLR/MOV) 0:05, 5. Lars Petter Nordhaug (NOR/SKY) 0:05, 6. Daniele Ratto
(ITA/LIQ) 0:05, 7. Michele Scarponi (ITA/LAM) 0:07, 8. Damiano Cunego
(ITA/LAM) 0:07, 9. Rui Costa (POR/MOV) 0:07, 10. Jean Christophe
Peraud (FRA/ALM) 0:07
1. Joaquin Rodriguez
(ESP/KAT) 20h 29min 18sec, 2. Samuel Sanchez (ESP/EUS) at 0:09, 3.
Robert Kiserlovski (CRO/AST) 0:26, 4. Lars Petter Nordhaug (NOR/SKY)
0:33, 5. Michele Scarponi (ITA/LAM) 0:33, 6. Sergio Henao (COL/SKY)
0:34, 7. Jurgen Van den Broeck (BEL/LTB) 0:35, 8. Ryder Hesjedal
(CAN/GRM) 0:40, 9. Damiano Cunego (ITA/LAM) 0:40, 10. Chris Horner