Lance Armstrong carried on playing mind games with his younger rival and teammate Alberto Contador on Sunday, hinting that he might be the strongest rider this year on the Tour and admitting for the first time that some tension exists on the Astana team.

TARBES, France — Lance Armstrong carried on playing mind games with his younger rival and teammate Alberto Contador on Sunday, hinting that he might be the strongest rider this year on the Tour and admitting for the first time that some tension exists on the Astana team.

With the race's toughest tests still to come, the 37-year old Texan has decided to put the pressure on the Spaniard's shoulders and to show he is still in control despite trailing Contador by a fistful of seconds overall.

After Sunday's ninth stage out of the Pyrenees mountains, the Texan is third — a solid result for a man coming back to competition after nearly four years in retirement. But the seven-time Tour champion wants more and has settled an appointment with second-placed Contador in the Alps.

"There's not going to be a lot of change until Verbier," Armstrong said, referring to stage 15, a grueling 128.9-mile trek between Pontarlier and Verbier, Switzerland. "We'll have more moments there when we'll see who's truly the strongest."

Despite losing 21 seconds to Contador at the first hilltop finish Friday in the Andorran ski resort of Arcalis, Armstrong seems convinced he can beat his Astana teammate in his quest for an 8th Tour de France triumph. Armstrong, who has meticulously previewed all the Alpine stages, even stated that he decided to let Contador go to favor his team interests when the Spaniard made his dazzling move in Arcalis.

"I wouldn't say that I could have easily followed, because it was an impressive attack," Armstrong said. "I probably could have gone, but I didn't see it coming and it wouldn't be correct for me to go across. So, I waited for the other guys. I expected them to be able to pull it back and they didn't, but that's life, that's cycling, and I had to do the right thing."

According to Armstrong and Astana manager Johan Bruyneel — a close friend to Armstrong — Contador went against the team's strategy when he attacked.

"The honest truth is that there is a little tension," Armstrong said Sunday on France-2 television, in the most explicit comments yet that their teamwork may be taking a back seat to their individual ambitions. "Contador is strong, and he is very ambitious."

The 26-year-old Contador has won all three Grand Tours of France, Italy and Spain — a feat accomplished by only five riders. Until now, the Spaniard has been careful not to speak to much about his ambitions, preferring to answer on the saddle.

"We knew that the Pyrenees were going to be the softest mountains on this Tour," he said. "Now I want to rest tomorrow and to stay calm during the first five days of next week before thinking about the next hilltop finish in Verbier."

With the Alps, a final individual time trial and the dreaded Mont Ventoux in the penultimate stage, the last week of the Tour will be crucial. Armstrong hopes to find his top form by then.

"That's my plan. I hope so. We'll see. There's no guarantees — I hope so," he said.

Before Monday's rest day in Limoges, Armstrong is third overall, eight seconds behind leader Rinaldo Nocentini, who is not seen as an overall threat. Contador, the 2007 champion, is six seconds back while other pre-race contenders are lagging well behind. Christian Vande Velde of the U.S. is eighth, 1:24 behind; Andy Schleck of Luxembourg is 1:49 back in ninth; defending Tour champion Carlos Sastre of Spain is 2:52 back in 16th; and Cadel Evans of Australia is 3:07 back in 18th place.

"Honestly, if I was Cadel Evans, or Andy Schleck, or Carlos Sastre, I would be waiting," Armstrong said. "I would wait for my moment in the Alps, on Ventoux, whatever, and I would stick it in as hard as I could. I would just pull the knife out and go."

While Contador has been linked to a move to the Caisse d'Epargne team next season and is likely to leave Astana, Armstrong confirmed he could extend his comeback by one more year. Asked by a French TV interviewer if this would be his last year at the race, Armstrong said: "Probably not. Probably not. Maybe one more Tour."

The seven-time champion, who is riding for the Astana team without salary this year, has previously hinted he may launch his own team next season.