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Who will win the US Open on both sides?
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Novak Djokovic moved into the U.S. Open semifinals for the 10th consecutive year when No. 9 Jo-Wilfried Tsonga stopped because of a hurt left knee, the defending champion's third opponent to pull out with an injury.
After the top-seeded Djokovic won the first two sets 6-3, 6-2 on Tuesday night, Tsonga was visited by a trainer and had his left leg taped below the knee. Tsonga double-faulted on the opening point of the third set, then retired from the match.