Cape Town - With the Rugby World Cup on the go in Japan, Swiss tennis star Roger Federer was quizzed on his knowledge of the oval ball.

Federer, who has won a record 20 Grand Slam singles titles, revealed in an interview with CNN Sport that he had practiced scrumming with his father while growing up.

Federer, whose mother Lynette was born in South Africa, also answered questions to test his general rugby knowledge.

He got some right, while some of his answers left much to be desired…

WATCH the interview in the video clip below: