Brydan Klein has lost out to Bjorn Fratangelo in the semi-finals of the Binghamton Challenger.
The British number six had been hoping to mark his recent impressive form with a place in the final in New York, but he struggled to make an impact against the second seed.
One break of serve was enough for the world number 125 to take the opening set before he struck two more times during the second to secure a 6-4 6-2 triumph.
Fratangelo will play either British number four Kyle Edmund or qualifier Sekou Bangoura in Sunday's final.
