Andy Murray bowed out in the Winston-Salem Open first round, while Lee Duck-hee made history on a rain-hit Monday (August 19).
Murray, playing his second singles match since undergoing hip resurfacing surgery in January, was edged by Tennys Sandgren 7-6 (10-8) 7-5 at the ATP 250 tournament.
The three-time grand slam champion, who accepted a wildcard into the event, had his chances before losing in two hours, 10 minutes.
Lee became the first deaf player to win a main-draw ATP Tour match, beating Henri Laaksonen 7-6 (7-4) 6-1.
The South Korean, 21, converted three of 11 break points in a historic victory.
Jeremy Chardy managed to get through to the second round courtesy of a 6-1 7-6 (7-5) victory over American qualifier Raymond Sarmiento.
Rain in North Carolina saw numerous matches postponed, with eight singles encounters completed.
Bjorn Fratangelo needed just 40 minutes to thrash Amir Weintraub 6-0 6-0 and Alexei Popyrin battled past Thiago Monteiro 5-7 6-4 7-6 (9-7).
Marco Cecchinato led Alexander Bublik 7-6 (7-3) 1-0 when the Kazakh retired, Pablo Andujar brushed past Nicolas Jarry 6-4 6-2 and Roberto Carballes Baena beat Marcos Giron 6-2 2-6 6-3.