John Isner (USA) rests in between games during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) keeps a close eye on the ball during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) reaches for a shot by Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits a forehand against John Isner (USA) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits a backhand against John Isner (USA) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) serves to Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits a backhand against John Isner (USA) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) watches his serve to Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) hits a forehand against Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) advances toward the net for this backhand during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) shrugs his shoulders at his coach Craig Boynton during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) pumps his fist after hitting a winner against Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) hits a forehand against Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) keeps his eye on the ball during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) hits a forehand against Gilles Muller (LUX) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits an awkward backhand against John Isner (USA) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits a backhand against John Isner (USA) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits a slice backhand against John Isner (USA) during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) follows through on a forehand during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

ESPN's Brad Gilbert looks up during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) hits a running backhand during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) hits a backhand during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) holds out his hands questioning his shot choice during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) hits a backhand during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) catches a ball from the ball boy during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

John Isner (USA) reaches for a backhand during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.

Gilles Muller (LUX) pumps his fist after winning the second set to force a third set during the semifinal match. John Isner defeated Gilles Muller in three sets 7-5, 6-7, 6-1 in the Semifinal Match on Saturday in the Atlanta Tennis Championships at the Racquet Club of the South in Norcross, GA.