British number two Aljaz Bedene caused an upset by beating world number 11 Gilles Simon to reach the last 16 of the Winston-Salem Open.
Bedene, 26, survived two match points to overcome the top seed 6-7 (5-7) 7-6 (7-5) 7-6 (8-6).
He will face Simon's fellow Frenchman Pierre-Hugues Herbert in the third round of the North Carolina tournament, which ends on Saturday.
"I haven't beaten someone in the top 10 yet, so this is my best win," he said.
"It was tough. Gilles is known as one of the toughest guys on the tour. Coming back after losing the first set, and having served for it, is never easy."
It was a third victory over a top-20 ranked opponent in 2015 for Slovenia-born world number 58 Bedene, who was granted British citizenship in March.
South African number two seed Kevin Anderson beat Mikhail Kukushkin 4-6 6-2 6-3 to progress, while France's Jo-Wilfried Tsonga went through 5-7 6-4 6-1 against Denis Istomin.