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VALENCIA, SPAIN - OCTOBER 30: Mischa Zverev of Germany returns a shot to Roberto Bautista Agut of Spain during day five of the ATP World Tour Valencia Open tennis tournament at the Ciudad de las Artes y las Ciencias on October 30, 2015 in Valencia, Spain. (Photo by Manuel Queimadelos Alonso/Getty Images)

VALENCIA, SPAIN - OCTOBER 30:  Mischa Zverev of Germany returns a shot to  Roberto Bautista Agut of Spain during day five of the ATP World Tour Valencia Open tennis tournament at the Ciudad de las Artes y las Ciencias on October 30, 2015 in Valencia, Spain.  (Photo by Manuel Queimadelos Alonso/Getty Images)