Sixth seed Alexander Zverev outlasted Frances Tiafoe 6-3, 3-6, 6-2, 2-6, 6-3 in the U.S. Open second round on Thursday. Zverev, who suffered a shock first-round defeat at Wimbledon last month, showed off his trademark endurance under the blistering sun on Arthur Ashe Stadium, saving eight of the 11 break points Tiafoe created on the German's serve. Zverev, who fired down 22 aces, appeared exhausted after a match lasting more than three hours. "Frances gave me an unbelievable fight," said Zverev. "IвЂ™m just happy to get the win somehow. Sometimes I would like to win easier than always five sets." The 22-year-old German was no stranger to his American opponent, leading him 3-1 in previous meetings, after they competed together in juniors competition.