PRATO NEVOSO, Italy -- Frank Schleck of Luxembourg seized the overall lead in the Tour de France on Sunday, drawing on his strength in the mountains and getting an assist from his brother as the three-week race headed into the Italian Alps.

"For me to take the yellow jersey, it's a childhood dream," Schleck said.

Cycling's premier event got a new leader on a day when Simon Gerrans of Australia won the 15th stage. It was his first stage victory in four Tour appearances, and he called it a "beautiful thing."

Riders confronted three climbs -- including one nearly 13 miles up the Agnel pass that is so tough it defies classification in cycling's rating system -- and an uphill finish to complete the 114-mile route from Embrun, France, to Prato Nevoso, Italy.

Schleck, who came into the stage just one second behind Cadel Evans, sped ahead at the finish to wrest the yellow jersey from the Australian. Schleck leads Bernhard Kohl of Austria by 7 seconds, while Evans slipped to third, 8 seconds back.

Schleck credited CSC teammate and younger brother Andy for surging ahead at least twice during the final climb in a bid to force Evans to work hard.

"Thanks, bro," Frank Schleck said.

Schleck has had success before in the Alps, winning a Tour stage in 2006 up the famed Alpe d'Huez, which riders will face Wednesday. He now wants to build his lead in the mountains, knowing that Evans most likely will be stronger in the time trial during the next-to-last stage before the July 27 finish in Paris.

Trying to move beyond a string of doping scandals, the Tour has gotten even tighter as it heads into the third and final week. Five riders are within 49 seconds of the leader -- up from three before Stage 15 started. Six riders have now worn the yellow jersey.

Some riders sensed Evans wasn't at his best Sunday.

"On a hilltop finish like this you don't need to have magic, you just got to have a strong team on the front," CSC rider Jens Voigt said. "Do hard tempo on the last climb, and our leaders take care of business. Put the hammer down basically."

Evans, who has said his team isn't the strongest in the mountains, came under repeated attack.

On the final climb, top contender Denis Menchov of Russia skidded off his bike on a sharp turn while leading one attack. He got back up and still finished 27 seconds ahead of Evans.

Menchov is fourth overall, 38 seconds back, followed by American rider Christian Vandevelde, 39 seconds behind. Spain's Carlos Sastre, also on Team CSC, trails by 49 seconds.

Gerrans, of the Credit Agricole team, led a four-man group that broke away from the main pack early in the stage and clocked 4 hours, 50 minutes, 44 seconds to beat Spain's Egoi Martinez in second by three seconds. U.S. rider Danny Pate was third, 10 seconds behind.

"It was a big surprise for me," Gerrans said in French, adding that he believed Martinez and Pate were better climbers than he is.

The race lost two notable riders -- Spain's Oscar Pereiro and Britain's Mark Cavendish.

Pereiro, the 2006 winner, broke his left shoulder when he crashed over a guard rail during a sharp turn. He was injured about 49 miles into the stage and was taken to a hospital in Cuneo. Pereiro won the Tour two years ago after Floyd Landis was stripped of his title for doping.

Cavendish, a sprinter who won four stages in this race, pulled out before a day of mountain racing. His team said he was fatigued and the Alps posed too big an obstacle. Cavendish will now concentrate on next month's Olympics.

Riders take the second rest day today before two more grueling stages in the Alps, starting with a 98-mile ride from Cuneo to Jausiers, France, on Tuesday that features two daunting climbs.