Tennis legend John McEnroe says Roger Federer must match Rafael Nadal's desire and intensity if he is to beat his long-time rival and reach the Wimbledon final.
The two rivals clash at the tournament for the first time since their classic 2008 final, which many consider to be the greatest match ever played, for a place in Sunday's final, which will be broadcast live on Eurosport.
McEnroe has hailed the competitive spirit with which Nadal approaches the game and says Federer must match that if he is to stand a chance of avenging his loss to Nadal in last month's French Open.
"You play against a guy like Nadal, the guy wants to tear your heart out, he wants to eat you alive," he told the BBC.
"I mean, he plays with such intensity. To me, the only chance you have when you play a guy like Nadal is you’ve got to try to match that."
I know when I played [Jimmy] Connors, who was our equivalent at the time, every point was like the last point you’re ever going to play. You try to look at yourself in the mirror and say, 'Am I doing as much as this guy?' and most of the time the answer is no.
"I get it’s so difficult to do, but you have to try."