Schleck attacked his Spanish rival several times as the pair duelled in the closing stages of an enthralling stage, but failed to shake Contador.
The victory keeps Contador eight seconds clear of the Luxembourger with just three stages remaining in the race.
Contador is expected to increase his slender lead during SaturdayÃ¢â‚¬â„¢s 52km individual time-trial; a discipline he has improved in significantly in recent years.
Schleck meanwhile will be left to rue his misfortune on MondayÃ¢â‚¬â„¢s stage when his chain fell on the ascent of Port de Bales.
Contador attacked the remainder of the stage, gaining 39 seconds as the riders descended furiously towards the finish line.
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