Serving for the match, the 6-foot-10 Isner fell behind 30-0 before Sela sent a backhand into the net, and then watched almost helplessly as the American ripped three straight aces for the win. Isner finished with 15 aces to Sela's two.
Ranked 12th, Isner has won two of his nine career titles in Atlanta, where he also lost to Mardy Fish in the 2010 and 2011 finals and to eventual champion Andy Roddick in the 2012 semifinals. In running his Atlanta record to 16-3, the former University of Georgia star had the crowd on his side on a 92-degree afternoon under bright sun.
''I consider myself very fortunate that this tournament is even here,'' Isner said. ''It's a big advantage to be in Georgia and have the support.''
Isner served beyond 140 mph on several occasions, while Sela was in the 115 mph range. Isner also crushed Sela's second serves, which often traveled at around 80 mph, to win 61 percent of Sela's second serves.
''I was able to get up early, and I was playing from ahead,'' Isner said. ''I like that situation a lot given the conditions and how I'm serving,'' Isner said. ''I think it was not so much that he was feeling the heat, but the conditions were different. The ball was so lively. My serve is tougher during the day than it is at night ... the ball was getting up on him a lot.''
Sela was playing in just his second ATP final after losing to Roddick in Beijing in 2008.
Isner earned $103,100, and Sela made $54,300.
American Jack Sock and Canadian Vasek Pospisil won the doubles title. Sock and Pospisil, the Wimbledon doubles winners three weeks ago in their first tournament together, beat American's Steve Johnson and Sam Querrey 6-3, 5-7, 10-5.