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Learner Tien of the U.S. signs autographs after defeating Daniil Medvedev of Russia in their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Learner Tien, left, of the U.S. is congratulated by Daniil Medvedev, right, of Russia following their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Learner Tien of the U.S. plays a backhand return to Daniil Medvedev of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Daniil Medvedev of Russia celebrates after defeating Fabian Marozsan of Hungary in their third round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Dita Alangkara
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Learner Tien of the U.S. plays a backhand return to Daniil Medvedev of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Daniil Medvedev of Russia plays a backhand return to Learner Tien of the U.S. during their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Learner Tien of the U.S. plays a forehand return to Daniil Medvedev of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Daniil Medvedev of Russia plays a backhand return to Learner Tien of the U.S. during their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
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Learner Tien of the U.S. plays a backhand return to Daniil Medvedev of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia. | Photo: AP/Asanka Brendon Ratnayake
