July 27 (Reuters) - Alex de Minaur outlasted big-serving American Reilly Opelka 7-6(4) 6-7(5) 6-3 on Saturday to reach the final of the Atlanta Open for the first time.
Despite the towering Opelka pounding 28 aces it was De Minaur who had the better serving on the day.
The Australian won 96 percent of his first-service points and never gave Opelka a break point opportunity on a hot and humid day in Georgia's capital.
The turning point came in the third set when De Minaur finally broke Opelka's serve to go up 3-2.
The 20-year-old broke again on match point when Opelka sent a backhand into the net for his 38th unforced error.
"Reilly is an incredible competitor, a super tough guy to play and a great friend," De Minaur said in a courtside interview.
"It's a bit of a lottery out here. I just had to guess the right way (when returning) on a couple (of) big points and I was fortunate to get the win today."
De Minaur will play in his fifth career ATP final on Sunday with his lone title coming earlier this year at the Sydney International.
Despite the loss, Opelka will enter the top 50 for the first time in his career when the new rankings are released on Monday.
In the final, De Minaur will face either Britain's Cameron Norrie or American Taylor Fritz, who were playing their semi-final later on Saturday. (Reporting by Rory Carroll; editing by Clare Fallon)