BAGNERES-DE-LUCHON, France -- Cadel Evans' hopes of retaining his Tour de France title collapsed Wednesday in the first day of Pyrenees punishment, losing ground to leader Bradley Wiggins in the 16th stage won by Thomas Voeckler.
Evans fell from fourth to seventh overall after struggling on the last two climbs out of four in the stage, while Wiggins wore the yellow jersey a little more comfortably.
Evans said he had been battling stomach problems.
"When you have it two hours before the race there's not a lot you can do," the 35-year-old Australian said. "I did not think it would affect me in the race, but obviously that's not my normal level.
"It's pretty much the Tour de France over for me."
Voeckler dominated the 197-kilometre (123-mile) course from Pau to Bagneres-de-Luchon, the Frenchman leading a breakaway for his second stage victory of the Tour. He also won Stage 10 and has four in total.
"Every one of the mountain passes was a race for me," said Voeckler, who captured the polka dot jersey for the best climber from Fredrik Kessiakoff of Sweden. "Today I did what many young riders dream of doing - leading everyone over all four summits."
"I knew every kilometre of this course today, and it served me well."
Chris Anker Sorensen of Denmark was second, 1 minute, 40 seconds back. The top title contenders - Wiggins, Sky teammate and compatriot Christopher Froome of Britain and Vincenzo Nibali of Italy - finished more than 7 minutes back.
The Tour was riding under a new doping cloud. RadioShack team leader Frank Schleck was expelled from the race Tuesday after testing positive for a banned diuretic.
Overall, Wiggins leads second-place Froome by 2:05 and third-place Nibali by 2:23. Jurgen Van Den Broeck of Belgium moved up to fourth, 5:46 back. Evans crossed nearly 5 minutes behind Wiggins to drop to 8:06 off the pace.
A bunch of 38 riders broke away early, but the big climbs took their toll and the group divided. Cyclists first scaled the Aubisque and Tourmalet passes - two of the toughest climbs in cycling - followed by the category-1 Aspin and Peyresourde passes. The last peak was 15.5 kilometres from the finish, before a long descent.
Voeckler grimaced, his jersey unzipped and his body rocking from side to side in rhythm with his pedal strokes as he climbed the ascents.
"I'm the first person to admit that I'm not beautiful on the bike," the Europcar rider said. "I'm a frowner ... That's my way of doing it - when I'm in pain, that's the way look."
After the three biggest climbs, the stage looked like a two-man race between Voeckler and Brice Feillu of France.
With 22 kilometres left, Voeckler stepped it up, pulling away. Sorensen then caught up with Feillu and overtook him.
On the ascent to the Aspin pass, the day's third big climb, Evans started to lag. The Australian couldn't keep pace with BMC teammate Amael Moinard of Belgium.
Evans was about 40 seconds back of his teammates, but recovered and joined the pack by the foot of the day's last climb after receiving an escort. But Evans struggled on the last climb, continuing to lose time afterward.
Evans crossed the finish line by clasping hands with U.S. veteran George Hincapie.
"The year's not over but certainly the retirement present I wanted to give to George Hincapie this year, the hope and wish for that is gone," said Evans.
Two American veterans ran into mishaps. Chris Horner, riding in his sixth Tour, had just fixed a punctured tire when he veered into some bushes, requiring a new bike to return to the race.
On the downhill from the Tourmalet pass, 17-Tour veteran Hincapie crashed and required treatment for his injured left shoulder and knee from team staff and the race doctor.
Thursday's 17th stage offers the last big day of mountain climbing, with a 143.5-kilometre slog up three hard ascents that includes an uphill finish from Bagneres-de-Luchon to Peyragudes.