Britain's Kyle Edmund was knocked out of the Chengdu Open in the second round by American Jared Donaldson.
The world number 46 was beaten 6-0 1-6 6-4 by 58th-ranked Donaldson, who was dominant on his first serve.
Edmund, 22, had seen off Bernard Tomic in the first round, but was broken once by Donaldson, 20, in the third set as his return from injury was halted.
The British number two retired in the US Open third round earlier this month because of a neck injury.
After a first set in which Edmund failed to win a game on serve, the Briton responded well in the second to level at 1-1.