Roger Federer has warned tennis's Big Three may continue to dominate the majors for some time yet as the ageless master readies himself for a 40th career showdown with Rafael Nadal.
Federer and Nadal, relative tennis pensioners with a combined age of 70, square off at Wimbledon for the first time in 11 years in Friday night's blockbuster semi-final at the All England Club.
After clashing in the 2006, 2007 and 2008 finals, few could have imagined the two great rivals would have to wait more than a decade before colliding again on tennis's greatest stage.
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Even more startling is how Federer and Nadal have managed to rack up 21 grand slam titles between them since their so-called greatest match of all time, won 9-7 in the fifth set by Nadal in 2008.
Such has been the dearth of challengers to Federer, Nadal and Novak Djokovic that, apart from three-time major champions Andy Murray and Stan Wawrinka, only Gaston Gaudio (2004 French Open) two generations ago, Juan Martin del Potro (2009 US Open) and Marin Cilic (2014 US Open) have also won a slam in the past 15 years.
The Big Three plus Murray and Wawrinka have not only won 57 of the past 60 majors, no active player under 28 has even contested a grand slam final.
It's an even more galling statistic considering Federer had already become men's tennis's all-time grand slam title leader with 15 of his now 20 majors before his 28th birthday.
"It's definitely not a - how do you say - regular time in tennis in the men's game," Federer said.
"I don't think we would have thought that Novak, me and Rafa, all of us, was going to be so solid, so dominant for so many years.
"I think that (collective domination), number one, stopped a lot of runs from the younger guys.
"Number two, I'm not sure, were they as talented as Rafa, Novak, and myself and others? Maybe also not."
Federer: Tough to get on top
Federer also believes the way rankings points are awarded makes it difficult for the younger generation to break through.
With the battle-hardened, thirty-something veterans entrenched in the top eight, it's tough for emerging talents to make their mark at slams and, thereby, rise in the rankings.
"The only way to get in there (near the top) at the moment, it seems like, if you win a slam. Otherwise you need so many more points in the 1000s," said Federer, who turns 38 next month.
"Rafa takes care of the clay there. Novak is in every Masters 1000 on hard court. I float around.
"You add Murray to it, Stan to it, guys that made their move later on, del Potro to it, you realise there's not that much to get.
"It's kind of tough to get to the top because Novak and Rafa are still so, so good. It just makes it more difficult like that."