British No. 2 Daniel Evans was defeated by Japan's Yoshihito Nishioka 6-2, 7-6 (3) in one hour, 49 minutes in the first round of the Korea Open on Tuesday.
Evans, the No. 5 seed for the tournament, has lost all six of his previous meetings with Nishioka.
Elsewhere, American Jenson Brooksby downed Taiwan's Tung-Lin Wu 7-6(5), 3-6, 6-0 in two hours, 22 minutes to advance to the second round.