Jannik Sinner will face Novak Djokovic in a Wimbledon semi-final on Friday, and the Italian shares John McEnroe's view about his opponent

Novak Djokovic is more than a decade older than any other man in the Wimbledon semifinals. He says it motivates him to see if he can keep going toe-to-toe against the younger players at the top of tennis these days.

Every other day at Wimbledon has brought an opportunity to compare the greatest player in men's tennis and one of his heirs.