Khachanov outlasts Tien in five sets in US Open last 16

Karen Khachanov came from a set down to beat Learner Tien 7-5 4-6 6-7 6-1 6-4 in the US Open round of 16, turning the match around with a one-sided fourth set before holding firm in the decider. The serve was the difference over four hours of shifting momentum: Khachanov landed 64.3 percent of his first deliveries and won 75.0 percent of those points, against 61.3 percent and 69.5 percent for the American. Both men were equally vulnerable behind the second ball, winning 46.7 percent, and Khachanov's nine aces just edged Tien's eight. The Russian moves through at the American's expense.