Philipp Kohlschreiber Pictures
NEW YORK, NEW YORK - SEPTEMBER 01: Philipp Kohlschreiber of Germany serves the ball during his men's singles third round match against Alexander Zverev of Germany on Day Six of the 2018 US Open at the USTA Billie Jean King National Tennis Center on September 1, 2018 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)