MONACO — Lance Armstrong put in a solid performance in his comeback at the Tour de France today, finishing the first stage ahead of 170 riders many years younger and a respectable 10th behind winner Fabian Cancellara.

Armstrong's Astana team was dominant in the time trial through the hills and hairpin turns of Monaco, led by the cyclist who would be his heir as Tour titan — Alberto Contador of Spain.

The Texan, who has a record seven Tour victories, is making his return to cycling's showcase event after ending a 3½-year retirement this winter. The 37-year-old Armstrong, one of the oldest riders in the pack, had a chance to test out his legs and state of mind.

"I was nervous, I was excited, and trying to focus on doing the right race specifically in terms of starting easy and finishing good," he said. "When I finished, I was tired — yeah, it was a hard race."

Cancellara took the yellow jersey by finishing the 9.6-mile time trial in 19 minutes, 32 seconds — 18 seconds ahead of Contador, the 2007 Tour winner.

"I didn't expect to win or to take the jersey. I didn't expect a super, super performance," Armstrong said. "It's been a long time since I've had that emotion of being on the start ramp at the Tour."

The race against the clock, in which riders set off one by one, offered an early shakeout about the potential contenders to win the three-week cycling showcase.

Contador showed he was ready.

"Fabian is a great champion ... (but) my form is very good," the 26-year-old Spaniard said. "I must try to keep up this level. I think I have started well."

Contador was forced to sit out last year because of doping problems at Astana before he joined. He is a far better climber than Cancellara, and the Pyrenees loom in Stage 7.

Contador led four Astana riders into the top 10. Andreas Kloeden of Germany was fourth, American Levi Leipheimer was sixth and rival Armstrong was 40 seconds back in 10th.

Contador got an edge on other title hopefuls. Two-time Tour runner-up Cadel Evans of Australia was 23 seconds behind Cancellara in fifth and Giro d'Italia winner Denis Menchov was 1:31 back in 53rd place.

Carlos Sastre, the reigning Tour champion, was 1:06 behind Cancellara. The 34-year-old Spaniard wanted to wear the yellow jersey, his team said, but Tour organizers have ended the tradition of letting the previous year's champion ride in it for the start after Floyd Landis was stripped of his title in 2006 over a doping scandal.

Much has been made of Armstrong's rivalry with Contador, who also stands a chance to become one of cycling's greatest riders. He has already won each of the Grand Tours of France, Italy and Spain — a feat accomplished by only five riders, and not Armstrong.

On his Twitter account, Armstrong hailed Leipheimer's "awesome" ride, but he didn't give an immediate reaction about the performance of Contador.

Armstrong, who rode 18th among the 180 riders to leave the start ramp, took the provisional lead early — baring his teeth and pedaling up out of the saddle as he neared the finish.

Only 15 riders later, Tony Martin of Germany outpaced him. Others also soon bettered Armstrong's time, including Leipheimer and Liquigas rider Roman Kreuziger.

"Kreuziger just moved into 2nd. I raced with his dad! Haha," Armstrong tweeted.

It was clearly an older Armstrong, not the Armstrong of old.

During his reign as Tour champion, Armstrong never finished lower than third in a time trial, except once, when he placed seventh in one in 2003.

"My heart rate — it didn't look exactly at the top, probably 196 (beats per minute maximum), so that's as hard as I can go," he said.

In another time trial in 2005, Armstrong outpaced Cancellara by more than a minute.

Cancellara, of the Saxo Bank team, will wear the overall race leader's yellow jersey for Sunday's second stage — a 16.2-mile ride across plains from Monaco to Brignoles, France.

"I think maybe in 5 years there are other riders coming and they will be faster than me. That's cycling — that's time," Cancellara said, when asked about Armstrong. "I also get older."

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AP Sports Writer Samuel Petrequin and AP Sports Columnist John Leicester contributed to this report.