Jimenez won the last two stages
The Swiss rider clinch the 208km stage with a sprint finish.
The overall leader Spain's Oscar Sevilla of Kelme, retained the leader's yellow jersey finishing in the main peloton 35sec adrift of the front pack.
He still has a 41sec overall lead over follow spaniard Festina's Angel Luis Casero.
Zberg crossed the line ahead of French Domo rider Richard Virenque and Spaniard Igor Flores, the trio coming in ahead of four riders who were part of a group which had maintained a breakaway for 100km of the stage.
Gap opened up
The leaders took full advantage of one of the many downhill stretches on the stage to part company with the main bunch 98kms into the race.
Green points jersey wearer Cesar Garcia Calvo and Spanish compatriot Juan Guillamon lead the initial charge.
By the time the front group had reached the summit of the final climb, the gap over the peloton had leapt to six minutes.
The leaders were then left in peace to ride unthreatened to the finish.
Virenque, who has been the Tour de France best climber on five occasions before becoming infamous for his part in the Festina drug affair, attacked with five km to go but lacked the necessary impulsion and he was soon joined by Flores and Zberg.
The 30-year-old Swiss rider then slipped into fifth gear for the final sprint finish.
Joseba Beloki meanwhile is unlikely to start Saturday's 14th stage after picking up a viral infection.
Beloki was seen in tears on Tuesday as he struggled in the 12th stage in the Pyrenees while wearing the leader's yellow jersey.
He currently sits in 27th place overall, nearly 21 minutes adrfit of current leader Sevilla.
Stage 13 standings
1. Beat Zberg, Switzerland, Rabobank, 4 hours 28 minutes 7
seconds.
2. Richard Virenque, France, Domo, s.t..
3. Igor Flores, Spain, Euskatel, s.t.
4. Rafael Diaz Justo, Spain, ONCE, s.t.
5. Dariusz Baranowski, Poland, ibanesto.com, s.t.
6. Roberto Sgambelluri, Italy, Telekon, s.t.
7. Juan Guilllamon, Spain, Jazztel, st..
8. Massimo Giunti, Italy, Cantina, 4 seconds behind.
9. Erik Zabel, Germany, Telekom, 35 seconds behind.
10. Sven Teutenberg, Germany, Festina, s.t.
Overall standings
1. Oscar Sevilla, Spain, Kelme, 42 hours, 2 minutes, 25
seconds.
2. Angel Casero, Spain, Festina, 41 seconds behind.
3. Juan Miguel Mercado, Spain, ibanesto.com, 2:02.
4. Levi Leipheimer, United States, US Postal, 2:19.
5. Jose Maria Jimenez, Spain, ibanesto.com, 2:50.
6. Roberto Heras, Spain, US Postal, 2:55.
7. David Plaza, Spain, Festina, 3:17.
8. Santiago Botero, Colombia, Kelme, 4:21.
9. Jose Maria Rubiera, Spain, US Postal, 5:27.
10. Iban Mayo, Spain, Euskatel, 5:32.