Fourth seed Isner, a towering player who relies heavily on his serve, initially struggled to find his range in the Winston-Salem Open final because of high winds brought about by Hurricane Irene.
He lost the opening set but adjusted his game and, once he found his rhythm, was able to take control.
"A lot of times in the wind you have to play to a big margin in the court and not to the lines. I was trying to hit the lines too much (early on)," he said.
"I started to be more aggressive in the second set. I told myself to get my intensity up.
(Editing by Tony Jimenez)
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