John Isner has survived two match points to claim the Atlanta Open, prevailing in a tense three-set battle 6-7(3) 7-6(2) 7-6(2) against Kevin Anderson.

A final between two big servers quickly went to a tie-break in the first set in a sign of things to come.

Inser managed to find four consecutive aces to save break point in the opening set, but Anderson's persistence paid off in the breaker as he took a one-set advantage.

Aces were a common theme in a tight second set, which also required a tie-breaker as both players continued to look formidable on serve.

Anderson pressed hard to force two match points, but on both occasions the American dug deep on serve to hold on.

That fighting spirit helped Isner level the match in a clinical breaker that forced a deciding set for the title.

The third set maintained a familiar pattern in the match, with a break of serve still proving elusive.

With the third set locked at 6-6, a final tie-breaker was needed to decide the Atlanta Open champion in a match that featured 45 aces.

Under pressure it was Inser who held his nerve, taking match point at the first time of asking with a fierce smash.

The 21-year-old prevailed in the longest ATP final on tour so far this year, claiming his seventh career title in a match timed at two hours and 48 minutes.