Rafael Nadal inches closer to year-end No. 1

Rafael Nadal pulled off one of the most unlikely comebacks of his career at the ATP Finals, beating Daniil Medvedev, 6-7(3), 6-3, 7-6(4). Nadal was 5-1 down in the deciding set when he saved match point and rallied to victory.

Why it matters: The win gave Nadal's hopes of finishing as the year-end No. 1 a significant boost, putting him 640 points ahead of Novak Djokovic, who must beat Roger Federer today to give himself a chance.

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