Defending champion John Isner overcame a slow start to advance to the Atlanta Open semi-finals, beating Australia’s Marinko Matosevic 7-6 6-4.

Isner’s service game was off as Matosevic broke the American in the first game of the match, and the top-seeded local had to fight off break points in his second and third service games to make the semis for a fifth straight year on Friday.

He was helped, too, by Matosevic’s six double faults.

Isner won the event last year after falling in the 2010 and ’11 finals to Mardy Fish.

Isner next plays the winner of Friday night’s quarter-final between American Jack Sock and Slovakia’s Lukas Lacko.

Benjamin Becker of Germany also advanced to the semi-finals after beating Thiemo De Bakker of the Netherlands 6-4 6-2.