Delray Beach: Donald Young toppled third-seeded Ukrainian Alexandr Dolgopolov 2-6, 6-3, 6-4 on Friday to book a semi-final showdown with Australian Bernard Tomic at the ATP Delray Beach Open.
Young, ranked 56th in the world, withstood 11 aces from the 24th-ranked Dolgopolov in a match lasting one hour and 56 minutes.
"I thought I fought well," said the American, who remains in search of a first ATP tour title. "I didn`t start off the way I wanted to. He was playing pretty well, hitting through the wind and controlling his shots quite good. I decided to buckle down, fight, go out swinging and got a little more not so conservative and it happened to work."
Young reached his fifth tour-level semi-final and his second in as many weeks after making the final four at Memphis.
Tomic, playing his fourth quarter-final of the season, ended the run of 19-year-old Japanese qualifier Yoshihito Nishioka 6-3, 6-1.
Tomic saved all seven break points he faced to dismiss the 154th-ranked Nishioka in less than an hour.
French fifth seed Adrian Mannarino moved a step closer to a first ATP title with a 3-6, 6-1, 6-1 victory over Taiwan`s Lu Yen-Hsun, who had toppled top-seeded South African Kevin Anderson en route to the quarter-finals.
Mannarino said he struggled early in chilly, windy conditions.
"Finally, in the second set, I tried just to focus on my legs and move better and try to be more consistent," the 26-year-old lefthander said.
Mannarino will face fourth-seeded Croatian Ivo Karlovic, who fired 17 aces in a 6-2, 7-6 (7/4) victory over seventh-seeded American Steve Johnson.