British number one Kyle Edmund lost 6-3 6-2 to Chile's Cristian Garin in the Chengdu Open first round in China.
World number 32 Edmund, seeded seventh, fell to defeat in 72 minutes against Garin, who is unseeded, but only one place lower in the rankings.
Edmund has now lost four successive matches and has suffered three consecutive first-round exits.
Fellow Briton Cameron Norrie is through to the second round at the Zhuhai Championships in China.
The world number 68 defeated Germany's Peter Gojowczyk 6-1 6-4.
Norrie will meet French third seed Gael Monfils in the second round.