Why do you play with left hand when you are right-handed: Federer asks Nadal

During an Instagram Live session, Roger Federer asked Rafael Nadal why he plays with his left hand when he is right-handed. Nadal replied "I cannot play righty. That's a legend! Everything else I do with right...but not...tennis." He added, "I started playing with...two-handed backhand and forehand. People I was working with probably didn't know if I was righty or lefty."