Alexander Zverev of Germany at the US Open in New York

Alexander Zverev of Germany reacts after winning the first set in a tie breaker against Philipp Kohlschreiber, also of Germany, during their third round match in Arthur Ashe Stadium at the 2018 US Open Tennis Championships at the USTA Billie Jean King National Tennis Center in New York City on September 1, 2018. Photo by Monika Graff/UPI