Washington (AFP) - John Isner claimed his fourth ATP Atlanta title on Sunday, saving a set-point in both sets en route to a 7-6 (8-6), 7-6 (9-7) win over Ryan Harrison.
The second-seeded American notched his second ATP title in as many weeks after lifting the trophy in Newport last week and Atlanta was the perfect place for him to keep the momentum going.
Isner, who has reached the final in seven of eight editions of the tournament, added a fourth title to those he won in 2013, 2014 and 2015.
Harrison, seeded fourth, was denied a second career ATP title, to go with his victory in Memphis in February.
"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."
Both players held serve throughout the opening set to force the tiebreaker, in which Isner faced a set-point at 5-6 but saved it with a booming serve.
He then converted a set-point of his own at 7-6 with a forehand winner.
Harrison ended Isner's run of 75 straight service holds - dating back to last week's Newport tournament - when he broke for a 2-0 lead in the second set.
But Isner broke back immediately, and they held serve to another tiebreaker.
Harrison made Isner work for it, saving a match point with a forehand winner before giving himself a set-point at 7-6.
"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."
His friend Isner responded with an ace, and went on to seal the victory on his second match point with a forehand winner up the line.
"It was a battle and took every ounce of my energy out there," Isner said.
"Just more importantly, I'm so happy to win this tournament again."
With the victory, Isner will move ahead of Jack Sock as the top-ranked US player.
"It feels pretty good for sure," he said.
"I've been the top American for the better part of six years now, so to be back in that spot is cool."