Thus, the minicamp. In Los Angeles, the task was to “clean up” all aspects of Isner’s game, as Gimelstob phrased it, and to put him through numerous repetitions in several categories. Those included shortening his backswing on certain shots and sharpening his volleying so that he felt more comfortable coming to net. They also focused on footwork, to improve Isner’s balance and his ability hug the baseline and punish an opponent’s second serve. They also worked on his racket-head speed and making a firm commitment to whatever shot he is making.

Isner’s powerful serve keeps him in most battles, and also produces many tight matches in which he and his opponent have trouble solving the other’s serve. Two glaring examples are Isner’s loss to Anderson at Wimbledon, and his 2010 victory over Nicolas Mahut that required three days and 138 games in the fifth set, the longest match in tennis history.

“I believe in the analytics of sports,” Gimelstob said. “Think about the math: What moves the margins in your favor? The margins in tennis are small. But there is no one whose margins are smaller on a match-to-match basis than John. Just watch him. So, most of our conversations are about what moves the margins in his favor. If you play the right way, over the course of time it will pay off with big results.”

Deciphering and applying voices from three coaches could challenge many players, but Isner says he relishes the triangular support, and he finds it refreshing to divide his travel, taking different members of the group to different tournaments. He will often rotate time with each one of the coaches individually, but they remain in contact with one another about the goals and the message.

“I have a very eclectic team,” Isner said with a chuckle. “A lot of different personalities into play. All three of them really get along and they supplement each other really well.”