ATLANTA (AFP) - Top-seeded John Isner kept his bid for a third straight Atlanta title on track Saturday, rallying for a three-set semi-final victory over qualifier and friend Denis Kudla.

Isner unleashed 25 aces and converted three of nine break chances to defeat his fellow American 4-6, 6-2, 7-5.

In Sunday's final he faces fifth-seeded Cypriot Marcos Baghdatis, a 6-7 (4/7), 6-3, 7-6 (7/4) winner over seventh-seeded Gilles Muller of Luxembourg.

Kudla, ranked 94th in the world and still seeking a first ATP title, broke Isner for a 4-3 lead in the opening frame and went on to pocket the set in 36 minutes.

Stung, Isner raised his game, blasting nine aces and breaking Kudla twice.

"I got stronger and stronger as that match went on," said Isner, who dropped just six points in as many service games in the third set. "I was feeling not so great in the first set, winded." The 22-year-old Kudla, a friend and sometime practice partner of Isner, noted the difference, particularly in the power of Isner's serve.

"He started flattening out his serve," Kudla said. "In the beginning, he was trying to pick his spots and I could get a racket on it. When he gets up toward 140 (miles per hour), that's when it gets tough." Baghdatis, playing his third ATP semi-final of the year, broke through to reach his first final since Kuala Lumpur in 2011.

On Sunday, the 30-year-old Cypriot will be seeking his first title since Sydney in 2010.

Serving for the match at 6-5 in the third, Baghdatis was unable to seal the win.

But he opened the decisive tiebreaker by breaking Muller's serve, and ended the two-hour, 36-minute match on his own serve on his first match point.