Rafael Nadal, a rival and 22-time Grand Slam champion, has been compared by Swiss legend Roger Federer to a "tiger in a cage" for his behavior on the tennis court.

In a recent ATP Tennis Podcast, 20-time Grand Slam champion Federer spoke about his friend and professional rival Nadal. In the 40 intense on-court encounters between the two players, Federer has tended to be cool and collected while Nadal has been all aggression. These two tennis greats competed side by side at the top of the sport for more than 15 years, thrilling fans with epic matches that Nadal won 24–16.

"I am very relaxed on and off-site, whereas he has an incredible intensity. He was like a tiger in the cage and he's going around and there's always stuff to do for him. You could always tell he had a match on his mind," Federer said in an ATP Tennis Podcast as quoted by ATP.

"I don't know if we're so opposite you know. But yeah, I guess, to some extent, I'm may be more calm more relaxed whereas he goes, especially through the tennis days in a more intense way when he's on-site," the 42-year-old Swiss player said.