My father gave me 2 years to succeed or go back to school: Federer

"My parents spent around 30,000 Swiss francs a year to pay for my tennis training (around 28,000 euros). But they were skeptical about my ability to become a professional player," the 38-year-old said in an interview with Die Zeit.

"When I was 16, I asked them if I should leave school to get 100% involved in tennis. My father gave me two years to succeed. If I failed or were unable to become a professional player, I had to go back to school. I told him to trust me and luckily I became World No. 1 in junior."

Federer has gone on to be recognised as one of the greatest male tennis players of all time. He has won 20 Grand Slam titles, the most for any male player in tennis history, has held the ATP World No.1 spot for a record 310 weeks. This included a streak of 237 consecutive weeks at the top of the rankings, which itself is a record.

He is also the only player after Jimmy Connors to have won 100 or more career singles titles, as well as to amass 1,200 wins in the Open Era.