British qualifier Jan Choinski threatened to produce a memorable victory from two sets down on his US Open main draw debut before running out of steam in a thriller.
Choinski, who won three qualifying matches to reach the main draw in New York, lost 6-2 6-3 5-7 7-6 (7-5) 6-3 to Spain's Roberto Carballes Baena in the first round.
The British men's number 10 ultimately paid the price for making too many unforced errors, particularly in the opening two sets.
He will also rue being unable to take any of five break points in the first game of the deciding set, having led 0-40.