Reflecting on his journey from Basel ball boy to Grand Slam king, Roger Federer cites his father handing him bus fare as a transformative moment in his life.

The 17-time Grand Slam champion concedes he was a bit of a tennis brat in his younger years sometimes tossing his racquet and barking at himself in frustration.

Federer: Novak Not Unbeatable, Rafa is Top Rival

Tired of the outbursts, Robert Federer, Roger's father, took decisive action: He handed his son bus fare and left him with a 45-minute trip home to reflect on his actions. About 67 seconds into this video for Nike's Roger Federer collection, the seven-time Wimbledon champion recalls the life-changing moment.

"I was playing with my dad and my attitude was always very temperamental and maybe not the best at times," Federer recalls. "And my dad would get frustrated. He said 'I don't enjoy playing with you like that.' So he put five Swiss francs on the bench next to me and said 'I'm leaving, I'll see you at home.'  And I couldn't believe he left me there because it was gonna be like a 45 minute bus ride back home."

Initially believing his father was bluffing, Federer credits his dad's decision for prompting him to assess his on-court behavior and take a more mature, disciplined approach to the game.

"So I waited for like an hour until he came back and he never showed up," Federer says. "And I realized he had actually left when I checked the car park... In a cute way, that's how it all started."

Unlimited Class from NIKELAB on Vimeo.

Photo credit: Nike