Canada's Denis Shapovalov, No. 4 seed, defeated Spain's Jaume Munar in straight sets to advance to the second round of the Korea Open on Wednesday.
Shapovalov won 7-5, 6-4, in one hour and 49 minutes to secure his first victory since his US Open third round defeat to Andrey Rublev.
The Canadian will face Radu Albot, who beat Steve Johnson in straight sets despite both going to tie-break.
Albot succeeded on his first of three match points to advance with a 7-6, (3), 7-6 (3) victory.
Elsewhere on Wednesday, Japan's Taro Daniel defeated Ecuador's Emilio Gomez 6-4, 6-4 to reach the second round.
Daniel will face Yoshihito Nishioka, who downed Britain's Daniel Evans on Tuesday, in the next round.