Swiss rider Gregory Rast retained the overall lead after a 222km leg from Ansbach to Bad Wurzbach but the day belonged to the man known as 'Ivan the Terrible'.

After the longest stage of the race, Quaranta powered past German sprint stars Erik Zabel and Olaf Pollack to claim his third victory of the season.

The 28-year-old said: "I saw Pollack and Zabel were watching each other (before the sprint), so I just waited then moved past them."

He described his win as the "hardest victory of my career,"adding: "I really had to fight for it."

Zabel admitted he had miscalculated his dash for the finish.

"I was too far ahead too early," said the Telekom rider. "And I underestimated the force of the headwind in the final straight."

Saturday's 191km fifth stage is between Ravensbourg and Feldberg.

Sunday sees a time trial over 40.7km around Bretten before Monday's final stage - 174.9km between Bad Duerkheim and Sarrebrucken.

Stage 4 results:

1. Ivan Quaranta (ITA) Saeco 4hr 52min 54sec
2. Stefan van Dijck (NED) same time
3. Jaan Kirsipuu (EST) s.t.
4. Olaf Pollack (GER) s.t.
5. Erik Zabel (GER) s.t.
6. Massimo Strazzer (ITA) s.t.
7. Jaroslaw Zarebski (POL) s.t.
8. Stuart O'Grady (AUS) s.t.
9. James Van Landschoot (BEL) s.t.
10. Fabian Cancellara (SWI) s.t.

Overall standings:

1. Gregory Rast (SWI) Phonak 19hr 06min 44sec
2. Gerben Loewik (NED) at 11secs
3. Erik Zabel (GER) 1:45
4. Gerrit Glomser (AUT) 1:56
5. Steffen Wesemann (GER) 1:58
6. Isidro Nozal Vega (SPA) s.t.
7. Michael Rogers (AUS) 2:00
8. Patrik Sinkewitz (GER) s.t.
9. Axel Merckx (BEL) s.t.
10. Joerg Jaksche (GER) s.t.

Euskal Bizikleta

Spain's Jose Antonio Pecharroman extended his overall lead by winning stage three on Friday.

The Paternina rider finished eight seconds ahead of countryman Miguel Martin Perdiguero to go 44 seconds clear of Italy's Francesco Casagrande in the standings.

Stage 3 results:

1. Jose Antonio Pecharroman (Spain) Paternina four hours 47 minutes 24 seconds
2. Miguel Martin Perdiguero (Spain) Domina Vacanze 8 seconds behind
3. Francesco Casagrande (Italy) Lampre
4. Joseba Beloki (Spain) ONCE
5. Aitor Kintana (Spain) Labarca 2
6. Haimar Zubeldia (Spain) Euskaltel
7. Leonardo Piepoli (Italy) iBanesto.com
8. Santiago Blanco (Spain) Relax Fuenlabrada
9. Roberto Laiseka (Spain) Euskaltel all same time
10. Ruben Lobato (Spain) Domina Vacanze 13

Overall standings: