British number two Dan Evans continued his losing streak against Japan's Yoshihito Nishioka with a straight-set defeat in the Korea Open.
Nishioka, who capitalised on a dropped serve in the first game, won 6-2 7-6 (7-3) in the first round in Seoul.
The 27-year-old has already beaten Evans, 32, in Miami and Washington this year.
Elsewhere in Seoul, Britain's lucky loser Ryan Peniston was also knocked out, beaten 6-3 7-6 (10-8) by Chile's Nicolas Jarry, who will next face top seed Casper Ruud of Norway.
However there was a win for British number six Liam Broady in the first round in Tel Aviv, after he beat Serbian wildcard Hamad Medjedovic 7-5 6-3.