Joseba Beloki, runner-up to the four-time champion last year and in second place entering the day, is finished with this Tour. He broke his right leg, wrist and elbow in a crash that nearly took out Armstrong, too.
"I was scared like never before," Armstrong said. "When you see something like that happening, the first thing you do is to say, 'OK, where am I going to go?' I couldn't make it to the right, I couldn't go over him, I could only go left. ... Then I found a little path there into the field and just continued on."
The cyclists were speeding down the day's last mountain, trying to catch leader Alexandre Vinokourov. Then Beloki braked, skidded on the slick and melting tarmac and hit the deck hard.
Armstrong was just behind and drove off the road into a field to avoid hitting the Spaniard. He recovered to finish fourth in the stage on Bastille Day.
The Texan bumped across the sun-baked grass to the bottom of the field, cutting off a hairpin bend. Then, he hopped off his bike to carry it onto the road, climbed back on and sped off in pursuit of the riders who had gotten ahead of him on the bend.
Above him, Beloki lay in agony. An ambulance rushed him to a hospital. Tour doctors said the star of the ONCE-Eroski team needed surgery for a broken leg and a cast for his elbow and wrist.
Going into the mountainous ninth stage of the three-week Tour, Beloki was just 40 seconds behind Armstrong.
"You hate to see a guy who's out there, doing his best and a real threat for the race, go down like that," said Armstrong, who is trying to match Miguel Indurain's record of five straight Tour wins. "I was lucky that the field was there like that. It could have been full of crops, it could have been a drop-off."
This Tour has been eventful for Armstrong. He had stomach flu in the weeks before the race, was involved in a crash on the second day and struggled with a faulty brake Sunday on a punishing climb.
Still, he retained the overall lead he first took a day earlier. But he has yet to stamp his authority on this race.
Vinokourov of Team Telekom won the 114.4-mile stage from Bourg d'Oisans to Gap. It was the Kazak's first Tour de France stage win and moved him into second place overall, just 21 seconds behind Armstrong with 11 days of racing left.
Vinokourov powered into the lead on the 2.5-mile climb to Cote de La Rochette, the day's last mountain just 5 miles from Gap. On the descent, Beloki and Armstrong were close behind and narrowing the gap when the Spaniard crashed on a slick corner just 2.5 miles from the finish.
"It was dangerous. All the corners were melting. There was asphalt but it was bubbling," Armstrong said.
"We came in too fast, he (Beloki) realized it, he locked up the back wheel," he added. "When the back wheel locks up it starts to slide out and he couldn't get it back under control. The tire blew, came off the rim and he lost control."
Armstrong was not penalized for skipping the bend when he went through the field because he did not gain time on rivals and did not do so deliberately.
Vinokourov completed the stage in 5 hours, 2 minutes, averaging 22.8 mph to a finish line painted red, white and blue to celebrate France's national day Monday.
Armstrong was in a group of 10 riders that finished 36 seconds back. Among them was Iban Mayo of Spain, who won Sunday's climb to the ski resort of L'Alpe d'Huez. He is third overall, 62 seconds behind Armstrong.
Also in the group were 1997 champion Jan Ullrich of Team Bianchi, who is sixth overall, 2:10 behind Armstrong, and American Tyler Hamilton of Team CSC. He's riding with a fractured collarbone, and is fifth overall, 1:52 back.
Vinokourov placed second at L'Alpe d'Huez, powering away from Armstrong up the ascent, as he did again Monday on La Rochette.
"I've never been so close to the yellow jersey and I've always dreamed of it ... Why not realize this dream?" he said. "I'm motivated and I'll do my best."
Monday's stage, the last of three in Alps, took riders past some of the most spectacular scenery so far, with glistening glaciers, mountain peaks, bubbling mountain streams and plunging gorges.
The riders scaled two peaks of more than 6,600 feet, including the 7,788-foot Col d'Izoard, a desolate moonscape of cliffs, scrappy grass and rock slopes above the tree line.
Stage 9 results, top 15 (Le Bourg-d'Oisans - Gap, 184.5 km)
1. Alexander Vinokurov (KAZ/TEL) 5hr 02min 00sec
(average: 36.656 kph)
2. Paolo Bettini (ITA/QST) at 0:36
3. Iban Mayo (SPA/EUS) 0:36
4. Lance Armstrong (USA/USP) 0:36
5. Jan Ullrich (GER/BIA) 0:36
6. Ivan Basso (ITA/FAS) 0:36
7. Georg Totschnig (AUT/GRL) 0:36
8. Francisco Mancebo (SPA/BAN) 0:36
9. Haimar Zubeldia (SPA/EUS) 0:36
10. Tyler Hamilton (USA/CST) 0:36
11. Roberto Laiseka (SPA/EUS) 0:36
12. Didier Rous (FRA/BLB) 0:52
13. Denis Menchov (RUS/BAN) 0:52
14. Christophe Moreau (FRA/C.A) 1:06
15. Roberto Heras (SPA/USP) 1:06
Stage 9 overall standings, top 15
1. Lance Armstrong (USA/USP) 40hr 15min 26sec
2. Alexander Vinokurov (KAZ/TEL) at 0:21
3. Iban Mayo (SPA/EUS) 1:02
4. Francisco Mancebo (SPA/BAN) 1:37
5. Tyler Hamilton (USA/CST) 1:52
6. Jan Ullrich (GER/BIA) 2:10
7. Ivan Basso (ITA/FAS) 2:25
8. Roberto Heras (SPA/USP) 2:28
9. Haimar Zubeldia (SPA/EUS) 3:25
10. Denis Menchov (RUS/BAN) 3:45
11. Roberto Laiseka (SPA/EUS) 4:03
12. Christophe Moreau (FRA/C.A) 4:04
13. Manuel Beltran (SPA/USP) 4:31
14. Georg Totschnig (AUT/GRL) 4:58
15. Pietro Caucchioli (ITA/ALS) 5:17