John Isner secured his fourth career Atlanta title on Sunday, beating compatriot Ryan Harrison in straight sets.
The second-seeded American defeated Harrison 7-6 (6) 7-6 (7) to claim his second successive ATP title after lifting the trophy in Newport last week.
Isner, who has reached the final in seven of eight editions of the tournament, added another title to those he won in 2013, 2014 and 2015.
"There wasn't much that separated us at all," Isner said. "So I'm happy to win that match in straight sets ... very happy to win today.
"It was a battle and took every ounce of my energy out there. Just more importantly, I'm so happy to win this tournament again."
Both players held serve throughout the opening set to force the tie-breaker, in which Isner faced a set point at 5-6 but saved it with a powerful serve, before he converted a set-point of his own at 7-6 with a forehand winner.
Harrison ended Isner's run of 75 successive service holds - dating back to last week's Newport tournament - when he broke for a 2-0 lead early in the second set but Isner broke back immediately before both players held serve to force another breaker.
Harrison saved a match point with a forehand winner before giving himself a set-point at 7-6. Isner responded with an ace, and went on to seal the victory on his second match point with a forehand winner up the line.
Harrison, seeded fourth, was denied a second career ATP title, to go with his victory in Memphis in February.
"We've both got that competitive side where we want to dig in and win," Harrison said. "I think there were times for each of us where things got a little frustrating, but we're really good friends so I really like John as a guy."
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