Teenage wildcard Taylor Fritz recorded the biggest win of his fledging career when he upset second seed Steve Johnson 7-6(7/5) 7-6 (9/7) at the Memphis Open.
Fritz dropped his serve in the opening game but then saved seven break points before securing a break of his own to take the first set into a tie break, which he won on his fourth set point.
Johnson missed the chance to level the match in the second-set tie-break before Fritz reeled off three points to a row to take victory.
Fritz told the ATP's official website: "It's funny because we practice with each other all the time, and he always breaks me in the first game. I guess we had to get that out of the way.
"Usually when I practice with him, I don't do so well. I usually don't win."
Fritz will play Benjamin Becker in the quarter-finals after he beat the seventh-seeded Australian John Millman 6-2 7-6 (/8/6).
Donald Young also advanced with a 6-1 7-6 (7/2) victory over Marcel Granollers and Ricardas Berankis beat Damir Dzumhur 6-3 6-4.
Source: PA