COURCHEVEL, France — Lance Armstrong moved closer to winning his second consecutive Tour de France and said his best is yet to come.
Armstrong put on another superb display of mountain climbing in the French Alps to finish fourth in the 15th stage Sunday to extend his lead over Jan Ullrich from 4 minutes, 55 seconds to 7:26.
A good performance in Tuesday's final mountain stage should clinch a win for Armstrong, but the 28-year-old Texan still wants to improve in the third and final week of the race.
"My form is not getting better," he said after Sunday's leg. "Things are similar to last year, with a good first few days in the mountains, then trying to maintain it.
"I still think my best day on this course is yet to come."
Armstrong finished 50 seconds behind stage winner Marco Pantani, the 1998 Tour de France champion.
The shaven-headed Italian powered past Jose Maria Jimenez in the final 1.8 miles of the 108-mile route from Briancon to Courchevel.
It was the second impressive 2000 Tour win for Pantani, who has barely raced at the top level since being thrown out of the 1999 Giro D'Italia for failing a doping test.
Armstrong cruised past the line knowing that Ullrich and Joseba Beloki, who finished third, were well-beaten.
With only one mountain stage left, there is little time for any other rider to catch Armstrong, who again looked in imperious climbing form.
After Monday's rest day, Armstrong just has to negotiate Tuesday's 122-mile course from Courchevel to Morzine, near the Swiss border, before the final flat stages to Paris.
Still, Armstrong, who battled back from cancer to win last year's Tour, isn't taking anything for granted.
"The stage to Morzine is very difficult and I refuse to believe that I have won the race until the very end. That is the attitude that is the most intelligent and the most respectful."
Though shorter than Saturday's marathon 155-mile route from Draguignan to Briancon, the 15th leg still had three tough summits above 2,000 meters to challenge riders' climbing skills.
Riders had to deal with chilly winds and sporadic showers, but for most of the journey north to Courchevel enjoyed sun and comfortable temperatures of around 59 degrees.
Of the 180 riders that began the race two weeks ago, only 141 remained.
The two hardest ascents were at Col de Galibier and Col de la Madeleine, before the final ascent up the Category 1 climb of Courchevel. A group of five riders led the charge up the final ascent.
In the final nine miles, Armstrong and Pantani chased the leaders while Ullrich fell behind.
Ullrich, who has suffered from weight and fitness problems this year, again struggled badly on climbs and finished 15th, 3:21 behind the winner.
"I was feeling good on Madeleine, but when Pantani attacked I had no strength left," said Ullrich, the 1997 Tour de France champion. "I am lucky still to be second."