Lance Armstrong puts the seal on what will be his seventh-straight Tour de France title by winning his first 2005 stage - the individual time trial.
The American clocks one hour, 11 minutes and 46 seconds to pip long-time rival Jan Ullrich in Saint Etienne.
Accidents permitting, he will be crowned champion on the Champs-Elysees after the formality of Sunday's stage.
Ullrich makes the move of stage 20 by eroding Michael Rasmussen's two-minute advantage to take third spot overall.
Click refresh for latest updates (all times BST):
1632: Armstrong wins the stage in 1:11.46 as the crowd goes wild. What a way for the Texan legend to complete his last professional time trial.
1631: Basso is in, but he is 90 seconds down on Ullrich. The Italian stays in second overall.
1627: Armstrong is quickest at the last check, 35 seconds ahead of Ullrich. Basso is paying the price for his early pace - he is fourth fastest at the last check.
1624: Ullrich sears into the lead in a time of 1:12.09.
1617: Armstrong is 30 seconds ahead of Ullrich's pace now as he bids to sign off in style.
1614: What a performance by Alexandre Vinokourov. He clocks the new best time of 1:13.02 secs.
1613: Armstrong scorches past Rasmussen, who started six minutes before him.
1611: Who else but Lance Armstrong is fastest at the 35km split. The American is 19 seconds ahead of Ullrich and 53 seconds quicker than Basso.
1609: As Basso seems to slow, Ullrich is at express pace. Maybe he can win the stage after all.
1605: Jan Ullrich is quickest at 35km by a massive 41 seconds, but Armstrong and Basso are going even quicker than he is.
1604: The latest chapter in the Rasmussen horror story sees the Dane cycle into a grass verge. He will just be hoping to finish inside the time limit.
1557: More woe for Rasmussen, who swaps bikes, but Vinokourov is the new leader after the third check.
1549: Rasmussen is having a torrid time - he has to stop for a puncture and Basso surges past him.
1547: Just like that, Ullrich is up into third place overall. Sensationally, Armstrong is slower than Basso to the first mark.
1545: Incredible scenes as Ivan Basso beats Ullrich's time at the first check by 17 seconds. That is a surprise.
1543: Bobby Julich smashes the target time, which now stands at 1:13.19.
1538: Ullrich is devouring Rasmussen's lead over him in the general classification. He is fastest to the 17km check and there is only 40 seconds between him and his quarry on the road now.
1531: These are worrying times for Rasmussen. Ullrich has already made up half of the two minutes and 12 seconds he needs to take over third place overall.
1528: Bobby Julich is fastest at 35km ahead of George Hincapie and Carlos Sastre, while behind them Alexandre Vinokourov is also flying.
1519: As Armstrong gets started, Rasmussen clips the corner and comes off his bike. That is a disaster for the man who is desperately fighting for third spot on the Paris podium.
1516: Off goes Rasmussen and he is followed by Ivan Basso. That leaves only one man at the start, none other than Lance Armstrong.
1512: Jan Ullrich gets under way - he is desperately trying to make up time on third-placed Michael Rasmussen.
1505: Suddenly Karpet's benchmark times are not looking so formidable. Bobby Julich, George Hincapie and Carlos Sastre all better him at the first check at 17km.
1450: The top-10 riders in this year's overall classification are getting ready to start.
1439: Vladimir Karpets sets a blistering time of 1:14.51. That will take some beating.
1415: Lang is the new leader with a time of 1:15.12 - but Karpets may beat that before long.
1357: Vladimir Karpets is setting the pace now from German Sebastian Lang - but neither rider has completed the course.
1344: Santiago Botero survives a near miss, skidding at a corner and almost taking out a group of fans. He is then passed by the speeding Vladimir Karpets, who started two minutes behind.
1310: Joseba Beloki, Stuart O'Grady and David Moncoutie are among the better-known names out on the course now.
1258: Australian Luke Roberts goes fastest in a quality time of one hour, 15 minutes and 33 seconds. But it is still unlikely that his time will stand scrutiny when the top riders hit the road.
1215: Fabian Cancellara sets the best time of the day at one hour 15 minutes and 49 seconds. He is the 24th rider out.
1120: Racing is under way, but no official times are in.
0940: Spain's Iker Flores is gearing up to get the individual time trial under way. As the 155th and last man in the race, he is first off the blocks. Lance Armstrong, as the race leader, goes last at 1522.