Sam Querrey came back from a set down to beat John Isner 3-6 7-6 (7-4) 6-4 in an all-American final at the Serbia Open on Sunday.
Isner, the second seed, threw away a 5-3 lead in the second set when he wasted a match point, allowing 22-year-old compatriot Querrey to take advantage.
Third-seeded Querrey then converted his fifth break point in the ninth game of the deciding set before serving out the match to claim the fourth ATP tour title of his career, and his first on clay.
"I feel great," Querrey told www.atptour.com, "It would feel better if I didn't have to beat my buddy out there and it was someone else. But it's still exciting.
"He's got the biggest serve in the game so it can be frustrating at times. But you just have to not let it bother you when you get aced and just walk to the other side to be ready for the next point.
"It's a game of inches, as they say."
Isner, whose powerful first serve appeared to have deserted him at crucial moments of the clash, threw his racquet to the ground in frustration after netting a forehand in the last point of the match.
"I had my chances, but he deserved to win," said Isner. "We'll be back the next year."
