Novak Djokovic and Roger Federer are not exactly the best of friends. There is a certain amount of animosity between the two players that dates back to a match in the Davis Cup in 2006.
While there might not be celebration lunches or dinners between the two in the future, the top two players remaining in the tournament, take court in familiar surroundings and in a familiar phase - the semi-finals of a Grand Slam.
Federer and Djokovic have met each other five times in the last-four in the past seven Grand Slams; the Serbian has got the better of the Swiss in most of those games and has beaten the 16-time Major winner in six of their last seven matches.
Wimbledon is another story though. This is Federer's backyard; he has won six titles in the grass courts in London and is one away from matching the record of seven Wimbledon crowns won by the great American Pete Sampras.
Federer breezed through the quarterfinals, hardly breaking sweat against a bemused Mikhail Youzhny. Djokovic, the defending champion, after his epic victory over Rafael Nadal in the final last year, is the form player though.
He gave the unbeatable Nadal a run for his money on the clay courts of Roland Garros and has already won the Australian Open.
"I'm not trying to defend my title here," Djokovic said. "I'm trying to fight for it as every other player who is in the last four. My mind-set is very positive. I obviously felt relief in a way that I won the tournament on the grass.
"But now I'm feeling great about playing on grass. This year I've been playing really well, consistently well, from the start of the tournament, and I hope to continue that way."
Federer, however, could regain the No 1 ranking if he beats Djokovic and goes on to win the title. Djokovic will remain the top ranked player, if he reaches the final.
"I've been playing well for a year now," Federer said.
"I'm happy that going ahead into the semi-finals I'm not tired, I'm not injured, I'm fresh and ready to go.
"That's how I want to feel. It's been a better tournament than in Paris for me anyway, where I struggled all the way through.
"Obviously I'm aware that Novak is the defending champion and the world No 1. That's not going to make it easy to come through.
"I know it's possible. I know I'm playing really well. I am aware things are going to get complicated. I'd better prepare well because it's going to be a tough match."
The other last-four match is equally intriguing. Andy Murray will look to end Great Britain's 76-year wait for a Grand Slam champion, and the first of two steps toward that will begin against the unpredictable Jo-Wilfried Tsonga.
Murray battled through a tough opponent in David Ferrer in the quarters and will be absolutely desperate to make the finals, after his draw opened up with the exit of Rafael Nadal in the second round. Frenchman Tsonga is capable of being great and mediocre within the same match. How Murray handles those situations will probably decide the outcome of the semi-final.
The Wimbledon faithful, so desperate for a home favorite to win, will be hoping Murray sees off the challenge of Tsonga, taking the Scot one step closer to ending 76 years of pain.
