Twenty-one seconds.

　　The slim lead that Lance Armstrong has as he embarks on the second half of the Tour de France is raising questions about whether the four-time champion can win a record-tying fifth title.

　　After 11 days of racing, he has just 10 more days to put his usual stranglehold on cycling's premier event. While he has the overall lead after three grueling days in the Alps, the 31-year-old Texan needs to do well in the upcoming Pyrenees to keep rivals at bay.

　　Second-placed Alexandre Vinokourov is just 21 seconds behind.

　　"It's perhaps the first time in four years where coming out of the Alps he's left a glimmer of hope," said Christophe Moreau, the top French rider so far, 12th overall. "It's not what we expected. Maybe he'll deliver a knockout blow in the Pyrenees or be knocked out himself," said the Credit Agricole racer, who is 4:04 behind Armstrong.

　　Yesterday was a rest day for the 171 riders still in the race.

　　Armstrong's next big day comes today with individual time trials where riders race against the clock. Armstrong, a bronze medalist in the event at the 2000 Olympic Games in Sydney, has alre-ady scouted out the hilly 47-kilometer course that should suit strong climbers like him.

　　His coach, Chris Carmichael, says that if all goes well, he expects Armstrong to gain 30 seconds over 1997 Tour winner Jan Ullrich, the silver medalist at Sydney, a minute over American rider Tyler Hamilton and more than two minutes over Spaniards Iban Mayo and Francisco Mancebo.

　　With those rivals close behind, Armstrong said it "may be the most important time trial I've ever done in the Tour."

　　Armstrong's hardly had an easy Tour. He battled stomach flu in the weeks before the race, was bruised in a crash on the Tour's second day and struggled Sunday with a faulty brake up the cruel climb over the 2,645-meter Col du Galibier.

　　Armstrong's race could have been over had he not reacted quickly to another crash. His closest rival, Joseba Beloki, skidded right in front of him on sun-melted tarmac on Monday, and Armstrong only managed to avoid him by plowing into a field next to the road. Beloki broke his right leg, wrist and elbow, ending his Tour.

　　Armstrong's US Postal Service team hopes its star's bad luck is behind him and say they remain supremely confident in his abilities.

　　"The Tour is always hard," teammate George Hincapie said. "We're looking forward to the Pyrenees. We're in the (leader's) yellow jersey - that's the main objective. There's a lot more compe-tition, we knew that coming in, but Lance is getting better every day."

　　This is not the first Tour Armstrong has started slow-ly. Last year, he was second overall, 26 seconds behind then-leader Igor Gonzalez Galdeano of Spain, by the first of the two rest days.

　　But 12 days later, he won the Tour by 7:17 over runner-up Beloki, his second-biggest margin of victory. Armstrong beat Switzer-land's Alex Zuelle by 7:37 in 1999, when he won his first tilte after battling cancer.

　　This year, Vinokourov sniffs an opportunity and is starting to believe he could be wearing the winner's yellow jersey at the finish in Paris on July 27. He won the last Alpine stage to Gap on Monday and was second on Sunday behind Mayo up the legendary climb to L'Alpe d'Huez, with 21 hairpin bends.

　　Before 11th stage from Narbonne to Toulouse, Mayo is in third place, 1:02 behind Armstrong. Mancebo, of the Ibanesto.com team, is fourth overall, 1:37 back. Ullrich, reputed as a rider who gets stronger in the Tour's second half, is 2:10 back in sixth, just behind fifth-placed Hamilton, who has a 1:52 deficit to Armstrong.