By Mike Burnett
BBC Sport at Wimbledon
Henman has some explaining to do over the 'cricket bat' incident
On court, the rivalry is intense - nerves, psychology and emotion all play their part.
But what goes on behind the scenes at SW19? What happens before and after the players make their entrance?
The Wimbledon locker rooms are probably the most famous changing facilities in the world, yet only a privileged few get to see inside.
One might expect players to sit there staring out their rivals in an atmosphere you could cut with a knife, but American doubles star Bob Bryan tells a completely different story.
"Usually on match days, you don't see the opponents talking," said Bryan, who has won three Grand Slam doubles titles with brother Mike.
"But every other day, it's kind of like a fraternity, people hanging out.
Federer's one of the most crazy guys out there
Bob Bryan on Federer's locker room antics
"Everyone's building each other up and kissing everyone's ass, hoping they'll get a little soft, so it's really funny."
In fact, tales from the men's locker room are the stuff of legend.
Former Wimbledon semi-finalist Tim Henman once recalled how he and Pat Rafter a few years ago, frustrated by another rain delay, decided to re-enact the Ashes.
Nadal's pretty intense, he's running around and that can be pretty intimidating
The pair got 15 other people involved, knocking a ball around with a cricket bat until someone got a bit carried away and damaged the ceiling with a slightly overzealous shot.
According to Bryan, the locker rooms are still a fun place to be and the most serious people on court can be completely different behind closed doors.
"Everyone thinks Roger Federer is so serious but you don't see this guy in the locker room," he told BBC Sport.
"Yeah before his match he's business but when he wins and gets a match under his belt, he loosens up.
"He's screaming at the top of his lungs, joking with everyone - he's one of the most crazy guys out there."
American Andy Roddick agreed, saying: "We get along really well.
"We always have a good laugh when we see each other in the locker room. I try to push him over and injure him."
Of course, things can get competitive too as players mentally prepare for matches.
Bryan revealed: "Rafael Nadal does all sorts of sprints and stuff in the locker room in front of his opponent.
Clijsters and Li enjoyed a good girlie gossip off court
"You've got to watch what he does in the locker room - it's pretty funny.
"He's pretty intense, he's running around and that can be pretty intimidating - that might be crossing the line but he's just getting ready for his match."
Of course the women's locker room has a few stories of its own.
Monica Seles was once nearly prevented from getting on court in time for a match by Martina Navratilova's pet Chihuahua.
According to legend, the dog was standing guard in front of Navratilova's locker, which was next to Seles'.
Every time Seles reached for a racquet, the dog barked forcing her to wait for the owner to return before she could get on court.
However, the women's changing room can be a more genial place these days.
Earlier this week, Chinese player Na Li revealed how she had enjoyed a good old fashioned girlie chat with Kim Clijsters before their quarter-final.
"Actually, I was talking with her already in the changing room," said Li.
"You know, as women, we always love to talk about things. Gossip, chatting, gossip, that kind of thing, yes."
Yes, the stakes are high and there is prize money to be won, but even top athletes cannot keep up the rivalry all the time.