Mardy Fish won the ATP Atlanta Championships for the second straight year on Sunday as he rallied to beat John Isner 3-6, 7-6 (8/6), 6-2 in a repeat of last year's final.
After losing the opening set Fish rallied from 1-5 down in the second set tiebreaker, saving two match points to level at a set each.
He then claimed victory through an early break in the third of Isner as the big man began to fade in brutal heat.
Number nine Fish improved to 3-1 overall against Isner and denied his compatriot and good friend a second straight title this month after his grasscourt victory at Newport the week after Wimbledon.
"I was lucky to come back in the tiebreaker" said Fish, who defended a title for the first time in his career and beat a fellow American for only the second time in seven ATP finals.
"When John is in that position he'll close out the match nine out of ten times."
Despite searing heat as he played in his first day match of the week, the top-seeded Fish said he felt good on court.
"John lives in Florida and I grew up there, the weather is hot and humid. You have to take care of your body. I'm very conscious of fitness now and pride myself on it. I felt good and thought I played great."
Fish, who is now the number one American in the game, said he had some lucky breaks, but he had never given up hope that he could rally.
"I'm not sure I can remember a fightback like that. But I always thought I had a chance, and hopes -- it was just a matter of time until I could get to him."
Fish claimed the sixth title of his career as he heads into next week's Los Angeles pre-US Open tournament as top seed.
After his heroics to knot the match at one set apiece, Fish opened the final set with a break as Isner's form began to melt.
Fish earned a second break for 5-2 on his opponent's sixth double-fault before serving out the victory a game later.
He claimed his first title since he beat Isner here a year ago for the inaugural Atlanta trophy, a confidence booster after Fish lost two Davis Cup matches against Spain earlier this month.