Tony Martin (HTC-Highroad) stormed to victory in the sixth stage of Paris-Nice, a
27km time trial in Aix-en-Provence, and now leads the race with just two stages remaining.
Wiggins had set a time that was rarely threatened until the HTC-Highroad specialist Martin began his ride.
He was 22 seconds faster than Wiggins at the 15km mark, and despite losing time to the Brit in the second half of the race, rode impressively to win by twenty seconds, with Porte a further nine seconds back.
However, the winner here in 2000 remains in contention, trailing by just 36 seconds.
The longest time trial in the race since 1968 ended any hope of victory for many of the pre-race favourites.
Michael Rogers (Team Sky) could only finish 22nd, beating his team-mate and early pace setter Geraint Thomas by just two seconds.
Frank Schleck (Leopard-Trek) lost over two minutes to Martin, while Jurgen Van Den Broeck came in three minutes 20 seconds of the pace.
Martin will surely be attacked in the final two stages, but with only Klöden and Wiggins within a minute of him, the 25-year-old may well have enough of an advantage to finish on the top step of the podium come Sunday.
Paris-Nice 2011, stage six: Rognes to Aix-en-Provence, 27km
1. Tony Martin (Ger) HTC-Highroad in 33-24
2. Bradley Wiggins (GB) Team Sky at 20 secs
3. Richie Porte (Aus) SaxoBank- Sungard at 29 secs
4. Andreas Klöden (Ger) RadioShack at 46 secs
5. Jean-Christophe Peraud (Fra) Ag2r at 55 secs
6. Lieuwe Westra (Ned) Vacansoleil-DCM at 57 secs
7. Andrew Talansky (USA) Garmin-Cervelo at 1-05
8. Rein Taaramae (Est) Cofidis at 1-10
9. Levi Leipheimer (USA) RadioShack at 1-10
10. Tejay Van Garderen (USA) RadioShack at 1-29
General classification after stage six
1. Tony Martin (Ger) HTC-Highroad in 24-59-4
2. Andreas Klöden (Ger) RadioShack at 36 secs
3. Bradley Wiggins (GB) Team Sky at 38 secs
4. Rein Taaramae (Est) Cofidis at 1-10
5. Jean-Christophe Peraud (Fra) Ag2r at 1-14
6. Levi Leipheimer (USA) RadioShack at 1-29
7. Janez Brajkovic (Slo) RadioShack at 1-32
8. Samuel Sanchez (Esp) Euskatel at 1-37
9. Xavier Tondo (Spa) Movistar at 1-51
10. Bauke Mollema (Ned) Rabobank at 1-57
Geraint Thomas put down an early fast time
Levi Leipheimer: Are those bars UCI legal?
Richie Porte: Third on stage
Andreas Kloden: Slipped to second overall
Bradley Wiggins: Great ride for second, and not a drop of dribble in sight
Tony Martin took the stage and went into the overall lead