Schleck's claims of unfairness wiped away by defiant Contador
In doing so, the 27-year-old reigning champion let his key rival know that he will need to go to war if he wants to top the podium in Paris on Sunday.
Saxo Bank climbing specialist Schleck went into the second of four days in the Pyrenees mountains with a 31sec lead on Spain's two-time champion.
But moments after "finally taking his responsibilities", according to Contador, and attacking the Spaniard inside the final two kilometres of the 19.3km to the Port de Bales summit, disaster struck.
Schleck had taken a 30-metre lead on Contador but just as the Spaniard began his counter move Schleck came suddenly to a halt. By the time Contador had closed the gap and passed the Luxembourger, Schleck was off his bike and screaming in frustration.
With Schleck left on his own to fix his mechanical problem, Contador raced ahead with Russian Denis Menchov and Spaniard Samuel Sanchez to crest the summit just over 20sec in front of the stricken Luxembourger.
The trio completed the 21.5km descent, later catching up with several breakaway riders who had been dropped by Voeckler, to finish 39sec ahead of Schleck who dropped to eight seconds adrift in second.
Schleck immediately slammed Contador and promised to take "revenge" in the coming days.
"I'm not the jury, but for sure those guys wouldn't get the fair play award from me today," said the 24-year-old.
However the Luxembourger has a short memory, according to Contador.
The Tour de France champion was among the riders and teams who went beyond gentlemanly fair-play and waited for Schleck and his brother Frank after both were among the multiple crash victims on the rain-hit stage two to Spa. But the Spaniard went further. Playing down Schleck's setback - which to most experts is simply part and parcel of racing - he said that he has race to win.
"I understand he's disappointed but what's important to me is that I took time off him. My goal is still to win the yellow jersey in Paris," said Contador. "Today Andy finally took his responsibilities (and attacked). But in any case I was ready to attack myself."
Schleck said after the race that it was "only fair" that his main rival and his Astana team did not take advantage of their setbacks on the way to Spa as the rain and slippery roads caused mayhem in the peloton. Had the boot been on the other foot, the Luxembourger claimed he would have waited on Contador.
"In the same situation I would not have taken advantage," said Schleck, who took the yellow jersey from Australia's Cadel Evans on stage nine.
Contador, who has won two Tour de France and the Giro d'Italia and Tour of Spain once each, let his experience do the talking.
"The race circumstances were different from Spa - there was no chance we could wait today. Some people understand and others don't, but that's just part of bike racing. It's a delicate issue that might create controversy, but I didn't even know he had a problem when I countered him.
"I don't know if the others knew what had happened. All I know is that they were all looking at me, and I wasn't the only one who was in front trying to increase the gap."
Contador added: "In Spa, I insisted to my team that we had to stop when the Schlecks crashed even before the decision was reached (by other teams).
"Anyway, I don't believe the time gaps at this point will decide the outcome of the race. There's still another two mountain stages left. But given the fact the gaps are really small, I won't be letting my guard down."
Johan Bruyneel to Schleck: No gifts
Andy Schleck was reminded that you can't rely on cycling's rules of etiquette as back-up after losing the Tour de France yellow jersey due to an untimely mechanical problem on Monday.
"There's no gifts in this race," said Johan Bruyneel, the Belgian who helped orchestrate all seven of Lance Armstrong's Tour triumphs.
Although Schleck slammed Contador for not waiting, and some of the crowd booed Contador at the finish line, others were quick to put things into perspective.
"It's just bad luck," said Australian Bradley McGee, Schleck's sporting director at Saxo Bank. "It was at the end of a really long and difficult climb and a lot of things were going on.
"We can't criticise anyone. Andy's a little bit upset, but now we have to come back stronger. Maybe we can turn his anger into positive energy tomorrow."
Saxo Bank team owner Bjarne Riis knows all about taking full advantage of rivals, having won the Tour de France in 1996 thanks partly to his use of the banned blood-booster EPO (erythropoietin), growth hormone and cortisone - a fact he admitted in 2007. And even Riis seemed to side with Contador.
"We're at a crucial part of the race, and that's just the way it is," said the Dane. "It's not great to lose the yellow jersey in this fashion, it's sad. But there is plenty of racing to do yet."
Bruyneel said the real issue was whether Contador knew Schleck had encountered a problem and deliberately tried to benefit, a suggestion the Spaniard refuted.
When Jan Ullrich crashed in 2001 Armstrong waited for his German rival, who returned the favour in 2003 when Armstrong crashed, along with Spaniard Iban Mayo, on the climb to Luz Ardiden in the Pyrenees. But Bruyneel was quick to remind Schleck that when the race is really on, you don't wait around for stricken rivals.
"The question is whether Contador was counter-attacking or just took advantage of a mechanical (problem)," said Bruyneel.
"In the heat of the race and in the final... you can't say to Contador, 'Hey, wait for Andy'. Andy didn't wait for Contador on the cobblestones (stage three) either, I guess.
"That's the proof that in cycling it can change from one moment to the other. Saxo Bank put in a lot of effort setting the pace because Andy wanted to attack. He put in a couple of attacks, and then in one moment it all changes and your main opponent takes advantage of your mechanical."
Armstrong admitted he had not yet seen the pictures, but said: "It's better to wait, but this is different. This was the last climb of the race and the race was really on."
Spaniards back Contador in Tour chain flap
The vast majority of Spaniards believe compatriot Alberto Contador was right to attack during the final kilometres of the 15th stage of the Tour de France even though rival Andy Schleck had suffered a chain malfunction.
Asked in online polls carried out by daily newspapers ABC, AS and El Mundo if Contador should have waited for Schleck, between 82 and 87 percent said no.
Sanchez, Menchov steal more time
Podium rivals Samuel Sanchez of Spain and Russian Denis Menchov boosted their hopes of a Tour de France podium finish after stage 15.
Euskaltel rider Sanchez began the day in third at 2min 31sec but took 39sec off Andy Schleck to finish the day only 2:00 behind new race leader Alberto Contador after the Spaniard stunned the Luxembourger on the race's final climb.
Overnight leader Schleck had attacked Contador in the final few kilometres of the 19.3km climb to the summit of the Port de Bales but suffered a mechanical problem which allowed Contador to take advantage.
Menchov and Sanchez were quick to jump on to Contador's wheel when the Astana man went on the offensive, but it was the Euskaltel rider who did most of the downhill work on the 21.5km descent. The trio raced together in a bid to distance Schleck, who was left chasing practically on his own with Belgian Jurgen van den Broeck (Omega-Pharma) on his wheel.
The Luxembourger, the runner-up to Contador in last year's race, eventually finished 39sec down on Contador's group to drop to eight seconds adrift in second overall.
Sanchez finished runner-up to compatriot Alejandro Valverde on the Tour of Spain last year, a race which is not as difficult as the Tour de France and which Rabobank rider Menchov won in 2007.
Menchov is still in fourth place, now at 2:13 behind Contador.
© AFP 2010