Phonak's Landis claimed the leader's jersey for the third time in the race following the 19th and penultimate stage, a 57km time trial won by unbeatable Ukrainian Serhiy Honchar of T-Mobile.

Landis, who finished the Tour's second race against the clock in third place at 1:11 behind Honchar, now has a 59sec lead over Spaniard Oscar Pereiro ahead of Sunday's final stage over 154km from Sceaux to Paris.

"It's one of the best days of my life. I don't want to give the yellow jersey away again," said Landis, who dramatically resurrected his bid on stage 17 having dropped to 11th overall at 8:08 a day before.

He put his efforts down to a simple recipe.

"I think I'm a person who works hard and I don't like to give up. Otherwise I'm just another human being."

Pereiro, of Caisse d'Epargne, raced last from the field in the yellow jersey beginning with a 30sec lead on Landis. Despite losing his jersey he dug deep to finish 2:40 behind Honchar to secure second place overall.

Germany's Andreas Kloden, of T-Mobile, set the second fastest time of the day at only 41sec behind Honchar, the winner of the first time trial on stage seven.

Kloden's efforts propelled him into the top three, and a place on the podium in Paris after he moved up to third overall at 1:29 behind Landis.

His performance, coupled with the collapse of CSC's Carlos Sastre meant the Spaniard dropped from second place to fourth overall at 3:13 behind Landis.

Australian Cadel Evans, who was overtaken by Kloden in the closing stages of their ride, despite starting three minutes before, finished 3:41 behind Honchar but that was enough for the Davitamon rider to hold on to fifth place overall.

Given the final stage is one in which the yellow jersey battle is not fought, Landis would have to fall ill or crash not to succeed his now retired compatriot Armstrong, whose team he left to pursue his own ambitions on the race.

The 36-year-old Honchar meanwhile had started the day 85th in the remaining field of 141 riders, and his time - thanks to powerful gearing and a sustained effort - proved the reference that most thought could never be beaten.

Honchar said: "It was a very good time for me especially as it was a very long and hard ride.

"I'm just happy I could perform so well after such a hard race."

Landis, the third last to start, had a storming start and came over the first time check at 16.5km a second ahead of the Ukrainian.

The 30-year-old American fell 26secs behind Honchar at the second time check at 34km, however the good news was behind him.

Pereiro, who began the time trial with a 30sec lead on Landis and a 12sec lead on fellow Spaniard Sastre, had lost 1:23 on Honchar and nearly a minute to Landis at 34km.

While Landis was tucked in an almost perfect aerodynamic position, the Spaniard was at times seen struggling to keep himself in the saddle.

Sastre meanwhile had virtually fallen out of contention having completed 34km 2:46 behind the Ukrainian.

At the third time check it was Kloden who had moved up to second place, at 47sec behind Honchar.

Landis appeared to be wilting, falling to third at 1:08, but with Pereiro at a minute behind the American there was little to worry him.