Roger Federer, Rafael Nadal, Andy Murray and Novak Djokovic have all contributed in their own special way to a golden age for men's tennis that will likely never be repeated. The quartet have won a total of 41 Grand Slams combined, which means the next generation have an almost impossible act to follow.
In reality, Federer - at 33 - is going to be the first to hang up his racquet. The others - all aged between 27 and 28 - hopefully have a few more years at the top of their game, but what happens after that time?
Some stars have started to display their credentials for challenging at the top, they're unlucky that they must learn their trade with such consistent performers bagging the Grand Slams.
If Wimbledon told us anything, it's that despite two familiar faces contesting the final, the up-an-comers are getting closer.
New big four?
So which quartet can move through the gears in time to take advantage of Federer's, Nadal's, Murray's and Djokovic's eventual fall from grace?
Agree, disagree or maybe you can think of some other names? If so, feel free to use the comment box below.