DELRAY BEACH, Fla. (AP) Donald Young upset third-seeded Alexandr Dolgopolov of the Ukraine 2-6, 6-3, 6-4 in the Delray Beach Open on Friday to reach back-to-back ATP Tour semifinals for the first time in his career.
On his sixth match point, the 25-year-old American finally put away Dolgopolov with a winner on a backhand volley.
Young struggled early, at one point cursing and throwing his racket in frustration.
''I didn't start off the way I wanted to,'' Young said. ''But then I just decided to go out swinging or I knew I'd be on a plane going home.''
Young will face Australia's Bernard Tomic for a spot in his first career ATP final. The two also played in the quarterfinals in Memphis last week, a 2-hour, 14-minute affair that Young won 7-6 (10-8), 4-6, 7-5.
Tomic beat 19-year-old qualifier Yoshihito Nishioka of Japan 6-3, 6-1. The 22-year-old Australian saved all seven break points he faced.
Fifth-seeded Adrian Mannarino of France also advanced, beating Taiwan's Lu Yen-Hsun 3-6, 6-1, 6-1.
Playing in temperatures in the mid-50s, Mannarino won 12 of 13 games after losing the first game in the second set. In January, he was lost to Jiri Vesely in the final in Auckland, New Zealand.
''In the beginning it was so cold that I had trouble keeping my fingers on the racket,'' said Mannarino, who beat Lu in straight sets at the French Open last year. ''I just had to concentrate, start moving my feet and keep the ball in the court.''
In the final quarterfinal, fourth-seeded Ivo Karlovic of Croatia survived two brief rain delays and a late surge by seventh-seeded Steve Johnson of the United States to advance 6-2, 7-6 (7-4.) The 35-year-old Karlovic hit 17 aces and saved two set points on his serve at 5-6 in the second set.
The 6-foot-11 Karlovic has not yet been broken this week and has only dropped his serve four times in 12 matches this year. He will face Mannarino for a spot in his 13th career ATP final.
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 win 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. Young then won four straight points to close out the victory.
After earning a career-high ranking of No. 38 in early 2012, Young lost 17 matches in a row over a span of six months, sinking to No. 190 by the end of that year. In 2013, he hired a sports psychologist to supplement the coaching of his parents, Donald Sr. and Illona.
He will move back into the top 50 with the win.
''Before, (losing match points) would have been it for me,'' Young said. ''Now I'm just focused and not worried about everything.''
His mother said a lot of that comes from maturity. She claims to share an inner energy and telepathy with her son that helps calm him during moments of distress. That became apparent when, after falling behind in the final game, Young shouted over to Illona, ''I need you now.''
He then won the next four points.