Check out the quarterfinals at the 2015 Mutua Madrid Open. There are more players 25 and younger than guys 30 and older.
Last year, Kei Nishikori was the only player in the quarterfinal under 25.
Nishikori, Milos Raonic and Grigor Dimitrov, all 25 or younger, earned spots in this year's quarterfinals. Nick Kyrgios, the 20-year-old Australian, fell one round shy of the quarterfinals after taking out No. 1 seed Roger Federer.
Kyrgios lost to John Isner, who last month became the eighth player aged 30 or older in the Top 20.
No longer emerging for the occasional upset, only to disappear, these next-generation superstars are here to stay.
Earlier this year, after capturing another Australian Open title, Novak Djokovic spoke to reporters about how these rising stars have begun to challenge the Big Four.
The gap is narrowed but it's still a long way for the new wave of tennis stars with the likes of (Milos) Raonic, (Grigor) Dimitrov and (Kei) Nishikori to make that step and break the domination of the top four guys.
They are close and they are challenging and they are knocking on the door but still if you see the winners of the grand slams it is still the top four guys.
Take a look out of your window, Djokovic. These guys are more than just knocking at the door. They are your neighbors now. They have taken up residence in the Top 10 and soon may step inside the Grand Slam chambers.
Nishikori and Raonic have become fixtures in the Top 10. Nishikori has reached a career-high No.4. This year, Nishikori has been in more semifinals and has one more title than Rafael Nadal.
Raonic, Nishikori and Dimitrov have all won ATP titles.
Even Bernard Tomic, who appeared on his way to bust status, is playing solid tennis this year. Tomic, who reached a career-high No. 26, was ranked in the low 80s around this time last year.
Often called the "Young Guns," when these players play each other, you get a sense that it's a glimpse into rivalries of the future..
The optics in the Kyrgios win over Federer reflect the reality that has beset the ATP: the generational shift has happened.
No more "what ifs" or "could be." It's done.
It's sort of like the generational shift in late-night television. Remember when NBC tried to force-feed Conan O'Brien, a Generation X entertainer, to the audience of baby boomers? Viewers were not quite ready.
Fast-forward a couple of years later and Gen Xers Jimmy Fallon, Jimmy Kimmel and Stephen Colbert have taken over late night television. Suddenly, Cold War jokes are out, and hip-hop sketches are in.
As with most generational shifts, the change was subtle but concrete. Bam, it's done.
Nishikori, Dimitrov and Raonic have shown promise for a few years. However, the real transition, the more substantive movement, began last year at the U.S. Open. Marin Cilic and Nishikori surprised everybody by reaching the final.
The trend continued at the 2014 Barclay World Tour Finals, where Nishikori, Raonic and Cilic qualified for the tournament. David Ferrer, the perennial top-eight finisher, was left out as an alternate.
Raonic was the first player born in the 1990s to qualify for the ATP finals. Nishikori was born December 29, 1989.
Last year, Djokovic began to recognize the youth movement after he defeated Dimitrov at the China Open. Djokovic told ATP staff:
I think it's logical to expect that in the sport, over time after so many years of dominance of three, four players, there are some others who are coming up and challenging. But on the other hand it's still not happening that they are the ones who are winning Grand Slams and being top three, four in the world.
It takes time. How long? I don't know.
Perhaps sooner than you think, Djokovic.