"I've gotten extremely hot about the idea of winning the Tour," the 29-year-old German said Tuesday, a rest day for riders. "At the moment everything is possible."
Ullrich has nipped at the heels of the four-time champion for much of the three-week Tour, trouncing him in an individual time trial last Friday and racing ahead on the first of four stages in the punishing Pyrenees.
But Monday, Armstrong struck back, overcoming a fall to power past Ullrich on a climb to a Pyrenean ski station and extend his overall lead over the German to 67 seconds.
That still isn't enough to faze Ullrich.
"I haven't been this close since 1997," he said, referring to the year in which he won the Tour, when Armstrong was battling testicular cancer.
It was the first time since the start of this year's Tour that Ullrich said victory was within his reach.
The expert time-trialist said he believes all will be decided by Saturday's race against the clock -- just one day before the race finishes on the Champs-Elysees.
"I am focusing on the time trial," he said.
On the relatively flat stages leading to Paris, he said his main goal was simply to avoid falling further behind.
In last Friday's individual time trial, one of only two on the Tour, Ullrich surprised even himself when be beat Armstrong by 96 seconds.
Ullrich said he nearly quit the Tour in the first week because of stomach problems and high fever.
Nevertheless, he persevered -- partly thanks to the strength he got from the birth of his daughter, Sarah-Maria, right before the Tour began July 5.
"When I call home in the evening and I hear the cries of the baby, that's the greatest thing there is, the pain immediately goes away," he said.
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Top 15 after Stage 15
*--* Place Rider Country Team Time 1 Lance Armstrong United States U.S. Postal 65:36:23 Service 2 Jan Ullrich Germany Team Bianchi 1:07 behind 3 Alexandre Kazakhstan Team Telekom 2:45 Vinokourov 4 Haimar Zubeldia Spain Euskaltel-Euskadi 5:16 5 Iban Mayo Spain Euskaltel-Euskadi 5:25 6 Ivan Basso Italy Fassa Bortolo 8:08 7 Tyler Hamilton United States Team CSC 9:02 8 Christophe Moreau France Credit Agricole 11:12 9 Francisco Mancebo Spain Ibanesto.com 16:05 10 Carlos Sastre Spain Team CSC 16:12 11 Denis Menchov Russia Ibanesto.com 17:09 12 Georg Totschnig Austria Gerolsteiner 18:52 13 Manuel Beltran Spain U.S. Postal 19:34 Service 14 Richard Virenque France Quick 22:00 Step-Davitamon 15 Roberto Laiseka Spain Euskaltel-Euskadi 24:19
* On the Web: For live updates of each day's Tour de France stage, complete standings, cyclist profiles and course information, go to latimes.com/tour