British number two Dan Evans lost his second-round match against Grigor Dimitrov at the Chengdu Open in China.
Evans, who was back in action for the first time since reaching the third round of the US Open, was beaten 7-5 7-5 by the Bulgarian former world number three.
The Briton, ranked 48 in the world, missed the chance of an early break in the opening set, which went with serve until Dimitrov closed things out in game 12.
Evans then found himself trailing 3-0 in the second when Dimitrov, the world number 26, held after a break before moving 5-2 ahead.
Although the 29-year-old fought back to break Dimitrov and then level at 5-5, the fourth seed took his second match-point chance to progress to the last eight, where he will face Alexander Bublik of Kazakhstan.