John Isner reacts Wednesday during his epic Wimbledon match, which is still ongoing.

When John Isner arrived at the University of Georgia, he was an average tennis player who was out of shape.

“He was not the most conditioned, health-oriented type of guy when he was a freshman,” recalled Manny Diaz, his UGA coach. “But I saw that he was just extremely gifted and a different type of tennis athlete.”

Diaz sat the 6-foot-9 player down during his sophomore year and tried to inspire him to take the sport more seriously.

"I said, ‘You have a gift. It’s a great lifestyle [to be a tennis player] and it’s going to a tremendous opportunity, but you are going to have to work for it. Or you can choose a typical path and work 8 to 5 like the rest of us for the next 35 to 40 years.”

The player heard his coach loud and clear. A bad back also spurred change in Isner.

The young player spent the next years, until he graduated in 2007, completely transforming his body and his game, Diaz said.

The epic match that finally ended: Isner beats Mahut

Isner first gained 40 pounds of muscle by changing his diet from pizza and soda to lean meats and veggies.

“He went from being our most inflexible athlete to our most flexible athlete by a mile,” said Diaz, describing how the player would spend hours with UGA’s medical staff to stretch and condition.

“What’s happening now is the culmination of years of effort,” Diaz said. “But I imagine with his size, he’s got to be hurting more. He must be much more sore than his opponent right now.”

Though there’s no doubt this week's marathon Wimbledon match with Nicolas Mahut will be inked in history books, Isner will not let it define him personally, Diaz says.

“He’s a combination of a great competitor who hates to lose and someone who is also confident in who he is,” the coach said. “He isn’t going to base his self-worth on what happens on that court today.”