LONDON -- Few players in recent history have been as helpful to the next generation as Roger Federer and Rafael Nadal. The all-time greats have continuously gone out of their way to extend invitations, whether for an exhibition or training, to their younger contemporaries. It's priceless insight into the minds of champions.
Still, despite the assists, these up-and-comers have by and large struggled to truly break through. In June, after his Wimbledon championship, Federer suggested the players who were expected to knock them from the top -- the likes of Grigor Dimitrov, Milos Raonic and Marin Cilic -- needed to be more aggressive and more imaginative on the court.
You can include Jack Sock among that group. On Sunday, Federer took care of the 25-year-old American 6-4, 7-6 (4) in the opening round-robin match of the ATP World Tour Finals.
Sock, who was coming off the biggest win of his career, the Paris Masters a week ago, spoke of his burgeoning confidence heading into the match. If ever there was a time he was going to take on Fed, it was now. But that confidence quickly devolved into reality, as Sock, who was broken in the first game of the match, became the latest to fall short against the 19-time major winner.
"Roger has played some outstanding tennis this year," Sock said afterward. "He puts a pressure on you that I feel no other player really does."
While Federer, 36, is a decade or more older than the future stars of the game, most of those players probably think the age gap is still too close. If only the so-called Next Gen were born a few years later and could hit their prime when Federer and Nadal were enjoying their retirement days.
"It is [frustrating]," Grigor Dimitrov said Friday at media day in London, where he has qualified for the first time. "I'm not going to lie. Even when you think you've put enough work in it, there's still that much to go.
"What we all forget is that while we're working, they're working as well."
If there is any silver lining, though, it's that he and the others next-generation stars understand they can be viable tennis players 10 years from now. "Age doesn't mean anything to me anymore," Dimitrov said.
By all accounts, Alexander Zverev looks like he has the most upside of the players looking to knock Federer and Nadal off their thrones. But the German, ranked No. 4 and who began his first foray into the year-end championships, still seems like someone more in awe of Federer and Nadal than a player ready to show the next generation has arrived.
"I think Roger and Rafa have been playing the best tennis of their lives this year," Zverev said at media day. "I really think that, especially Roger. He's only lost four matches this year. It's quite amazing how he's able to play at 36 years old.
"And Rafa on clay, winning a Grand Slam losing three games in a set, max, is something that I don't know if we've seen before."
Until 2017, 50 of the previous 54 Masters 1000s events were won by either Federer, Nadal, Novak Djokovic or Andy Murray. But this year, Zverev (Rome and Montreal), Dimitrov (Cincinnati) and Sock (Paris) have all bagged Masters.
It's a terrific effort, especially when you consider the monopoly the Big Four had at these events. And perhaps it's the first step toward winning majors, where Federer, Nadal, Djokovic and Murray have taken home 49 of 57 trophies since 2003.
"All of us are working hard to try to replace them a little bit," Zverev said. "This is what we're all working for, to win the biggest tournaments in the world."
But as Sock pointed out, that time might need to wait longer. Even when Federer isn't striking the ball perfectly, according to Sock, his shots still seem to land inside the court. And when Federer is on like he was Sunday, crushing his backhand passing shots and pulling off a between-the-legs half-volley, well, forget it.
"I don't know, it is Roger, I guess," Sock said. "He can do no wrong. Everything goes in."
And as long as everything continues to go in, the wait for the next generation to break through will go on.