Contador held an eight-second advantage over his rival going into the timed stage and a strong finish over the final third of the course put the title in his grasp despite a valiant effort from Luxembourg's Schleck who is now set to finish runner-up for the second successive year.
Sunday's final stage is a 102.5-km ride to the Champs-Elysees in Paris, traditionally a day-long parade.
”It's very emotional, it was so very difficult. I trained very hard all year. I kept focused and this was a hard Tour until the last minute,” said Contador, who cried when receiving the yellow jersey on the podium.
The Spaniard said he had not been as dominant as last year, when he beat Schleck by over four minutes.
The 39-second gap between the pair was identical to the one obtained amid controversy by the Astana team leader in Monday's 15th stage to Bagneres de Luchon when his Luxembourg rival was hampered by a mechanical fault.
Schleck fought bravely on Saturday and if Contador, who had always comprehensively beaten Schleck in time trials, was expecting a lap of honour in the Bordeaux vineyards, he was mistaken.
Schleck had promised to die on his bike to defend his last yellow jersey chances and he was true to his word for 40 kilometres, even taking some time off the Spaniard in the first 30-kms.
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