British number three Kyle Edmund lost in straight sets to defending champion Guillermo Garcia-Lopez in the second round of the Nastase Tiriac Trophy.
The Spaniard, 32, won 6-3 6-3 in Bucharest to deny 21-year-old Edmund a first clay-court quarter-final.
Edmund, ranked 55 places lower at 92 in the world, saved nine of 12 break points but could not force one on the Garcia-Lopez serve.
The match had been postponed on Wednesday because of heavy rain.