Graham spends two days in Belgrade, Serbia, with No. 1-ranked tennis player Novak Djokovic. The 17-time Grand Slam champion eyes the all-time record, discusses how war has shaped him and reveals how his marriage proposal almost literally went up in flames. Djokovic shows Graham around the city with stops at his tennis center, childhood playground and local gym. Plus, Graham spends time with Djokovic's wife, mother, friends and family to learn what it is like to support one of the greatest athletes of all time.