Donald Young upset third-seeded Alexandr Dolgopolov 2-6, 6-3, 6-4 at the Delray Beach Open on Friday to reach back-to-back semifinals on the ATP Tour for the first time in his career.
On his sixth match point, the 25-year-old American finally put Dolgopolov away with a winner on a backhand volley.
A decade ago, Young was the world's top-ranked junior, but he has struggled to fulfill that promise on the pro tour.
Young had five chances to clinch the match on Dolgopolov's serve in the final set. Dolgopolov saved all of them, and he won the first two points against Young's serve in the next game.
But Young then won four straight points to close out the victory.