Mark Cavendish of Britain collected his sixth stage win of this year's Tour in a sprint after the 164-kilometer (101.9-mile) course ride from Montereau-Fault-Yonne to the Champs-Elysees.
Over nearly 3,500 kilometers and 21 stages of races over three weeks, Contador repelled many challenges in the mountains, excelled in the two time-trials — winning a pivotal race against the clock in the 18th stage — and won the first Alpine stage.
Contador, the 2007 champion, also had to battle a rearguard action within his Astana team, where the comeback of Armstrong to the Tour after 3 1/2 years of retirement raised questions about who would be the team leader.
He had to sit out last year because of a doping scandal at Astana that erupted before he joined.
Armstrong, the 37-year-old seven-time Tour champion, is the second-oldest rider to reach the Tour podium. Raymond Poulidor of France was 40 he placed third in 1976.
Cavendish set his own record: no rider has ever won six Tour stages in a sprint. But Thor Hushovd of Norway beat the 24-year-old Briton for the green jersey given to the Tour's best Tour sprinter.
"It's amazing. I'm so happy to be here," Cavendish said. "Six stage victories on the Tour — all my dreams have come true."