Some athletes are born with speed, some with size, others naturally intelligent or tenacious, but every professional athlete inherently possesses an innate ability to perform. They step up their game when everything is on the line. Luckily for John Isner, the majority of these character traits are intrinsically developed. The record-setting racket master recalls an unforgettable week at Wimbledon, where he won a match that lasted a daunting eleven hours. No, seriously, eleven hours. After spending three days trying to decide a single set, Isner’s mental fortitude literally kept his head in the game, mainly because his legs probably felt like mashed potatoes. He has this unrelenting will to persevere in the face of adversity, and it’s one reason why we’re such huge fans.