Alex Zuelle was poised for back-to-back Tour of Spain triumphs on Saturday after a 50 kph dash to victory in a 43.7 km time trial.
Zuelle should now give Switzerland their fifth victory of the Tour in six years in Madrid on Sunday following 3,760 km of racing.
He was two minutes 21 seconds faster than Spanish rival Fernando Escartin who goes into the final stage five minutes seven seconds adrift.
Zuelle covered the time trial circuit on the outskirts of Madrid in 51 minutes 35 seconds, 31 seconds faster than Ukrainian Sergei Gontchar and 40 seconds better than Spain's Alberto Leanizbarrutia.
It was Zuelle's first stage win in the 22-day race which he had started, according to team manager Manolo Saiz, ``overweight and out of shape,'' after a lay-off following injury.
``It is a great day and twice as good to win the stage and keep the yellow jersey,'' said the Swiss who still carries 12 surgical pins in a collarbone fractured in June.
In the final eight kilometres Zuelle overhauled Escartin who had started two minutes before him. The Spanish rider was more intent on protecting his second overall position from the threat of another Swiss, Laurent Dufaux.
Escartin finished 17 seconds faster than Dufaux and guaranteed Spain a top three placing which they missed out on last year for the first time since 1987.
The closing 22nd stage takes the riders 148.5 km through the suburbs of Madrid on to a 10-lap five kms circuit to a finish on the Paseo de la Castellana in the city centre.
1. Alex Zuelle (Switzerland) ONCE 51.35 2. Sergei Gontchar (Ukraine) AKI 0.31 3. Alberto Leanizbarrutia (Spain) ONCE 0.40 4. Laurent Jalabert (France) ONCE 0.51 5. Melchor Mauri (Spain) ONCE 0.56 6. Tony Rominger (Switzerland) Cofidis 1.26 7. Juan Carlos Dominguez (Spain) Kelme 1.30 8. Cristian Salvato (Italy) Refin 2.13 9. Enrico Zaina (Italy) Asics 2.19 10. Fernando Escartin (Spain) Kelme 2.21 11. Jose Vicente Garcia Acosta (Spain) Banesto 2.31 12. Roberto Heras (Spain) Kelme 2.35 13. Laurent Dufaux (Switzerland) Lotus 2.38 14. Sergei Ivanov (Russia) TVM 2.39 15. Francisque Teyssier (France) GAN 2.42 16. Bruno Thibout (France) Cofidis 2.52 17. Jacky Durand (France) Casino 2.56 18. Carlos Contreras (Colombia) Flavia s.t. 19. Gianni Faresin (Italy) Mapei 2.57
1. Zuelle 87.46.13 2. Escartin 5.07 3. Dufaux 6.11 4. Zaina 7.24 5. Heras 8.04 6. Clavero 10.02 7. Jalabert 10.03 8. Marcos Serrano (Spain) Kelme 10.40 9. Faresin 13.53 10. Yvon Ledanois (France) GAN 15.40 11. Chiappucci 16.22 12. Philippe Bordenave (France) Casino 18.21 13. Felix Garcia Casas (Spain) Lotus 18.47 14. Jose Manuel Uria (Spain) Estepona 19.42 15. Contreras (Colombia) Flavia 20.46 16. Marco Serpellini (Italy) Brescialat 22.11 17. Paolo Lanfranchi (Italy) Mapei 30.35 18. Dominguez 31.23 19. Laurent Brochard (France) Lotus 31.51 20. Rodolfo Massi (Italy) Casino 31.59