Frequent practice partners John Isner and Jack Sock are Saddlebrook neighbors, but Isner was feeling some separation anxiety facing his friend today.

The defending Atlanta champion could not get close to Sock's serve.

Isner closed the gap by stepping closer to the baseline and imposing his sledgehammer forehand — and mounting scoreboard pressure — to break in the final game of both sets. The result was a 7-5, 6-4 victory that sent the former University of Georgia Bulldog into his fourth Atlanta final in the last five years.

Two weeks ago, Isner carried a 13-match winning streak against fellow Americans into the Newport quarterfinals where Sock edged Long John for the first time, 6-4, 7-6 (4), on the Hall of Fame lawn. Sweltering conditions made the scorching first serves and twisting second serves of both men even more hazardous to the returner on hard court today. Sock issued three love holds and dropped only two points on serve through his first five service games.

Catching up to Isner's serve on hard court requires more than quick reflexes, you've got to move early and guess right or resign yourself to that ominous thud off the back wall.  Blocking back returns like volleys, Sock pressed Isner to deuce in the ninth game, but chipped successive returns into net. Isner went for an ambitious second serve, but missed the center stripe handing Sock the first break point of the match in the 11th game. Reading Isner's approach, Sock crouched low and was in good position for a backhand pass, but drove the shot into the top of the tape. The world No. 12 held for 6-5, then made Sock feel the stress.

The 21-year-old Nebraskan possesses a live arm, booming serve and electric forehand, but his game is still a work in progress. Sock sometimes stiff arms his crosscourt backhand, his footwork can get sloppy dancing around the backhand to hit his favored forehand and he must sharpen his shot selection. Repeatedly trying to end points prematurely by strong-arming his forehand down the line rather than stretching the big man to his weaker backhand wing, Sock paid the price.  He netted a forehand down the line to face a third set point then steered a crosscourt backhand wide as Isner broke with a scream, ending an eight-deuce game and leaving a cranky Sock bouncing his Babolat off the court and barking at himself in frustration.

The second set followed a similar script as Sock gained the first break point, but could not convert in the fifth game. Ruing that lost opportunity, Sock played a distracted sixth game to face double break point. He erased the first with a backhand pass down the line and saved the second with a crackling forehand winner, eventually holding for 3-all.

Isner is imposing on American hard courts — 15 of his 18 finals have come on home soil — because of that explosive serve, volatile forehand and unsettling knack of looking punch drunk from fatigue only to pound the ball with bad intentions and rattle the opponent. Sock saved two match points, but netted a forehand and spun a double fault wide to end the 97-minute encounter and his bid for a first ATP final.

The 29-year-old Isner, who has won six of his eight career titles in America, will face either Dudi Sela or Benjamin Becker in Sunday's final. Isner is 3-0 against Becker — all on hard courts — and has won both meetings versus Sela, including a 3-6, 6-1, 7-6 (5) victory in Delray Beach earlier this year.

"Historically, I've always played well in the States — especially in the summer," Isner told the ESPN2 crew afterward. "I feel like it's my turn to shine."