Year after year it seems to be the same question: can anyone truly compete with Roger Federer, Rafael Nadal or Novak Djokovic at the grand slam events?
As they continue to advance into their thirties it becomes increasingly likely that their reign of supremacy will end and their unrelenting grip on the major tournaments wane.
Yet time and time again they have let their tennis do the talking and proven why, as Wimbledon gets underway today, they remain the world’s top three and the greatest male players to have graced the game.
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You have to go back 11 grand slams to Stan Wawrinka’s US Open victory in 2016 for the last time anyone other than Federer, 37, Nadal, 33, or Djokovic, 32 – the defending champion in SW19 – claimed a major title.
Where is the next generation?
Their dominance is nothing new; between them they have won an astonishing 53 slams, and it is difficult to see anyone halting that sequence at the All England Club over the next fortnight.
In fact, there is only one man aged under 30 who has won a single set in a grand slam final: Dominic Thiem, 26, who claimed one in his 3-1 defeat by Nadal at this year’s French Open.
Marin Cilic was the previous player outside that peerless trio to do so, winning two sets in his loss to Federer at the 2018 Australian Open, although the Croatian is now 30 himself.
Aside from Thiem, there are only two other players currently in their twenties to have even reached a grand slam final.
Milos Raonic, 28, lost the 2016 Wimbledon final in straight sets to Andy Murray, while Kei Nishikori, 29, did likewise in the 2014 US Open to Cilic. Neither man has been back to one since.
And the only other players to have reached grand slam finals in the last six years are Juan Martin del Potro and Kevin Anderson. But both have passed the 30 mark.
It all screams the question: where is the next generation?
Thiem and Zverev flatter to deceive
Thiem looks the most likely of anyone to inherit Nadal’s crown as the king of clay, having been runner-up at Roland Garros for two consecutive years. But, at 26, he could be near to or older than 30 himself by the time his Spanish counterpart, 33, retires.
Current world No5 Alexander Zverev is another player that has been mixing it in the top 10 for a couple of years now, but has yet to make his mark on any of the major tournaments.
His best results to date at grand slams are quarter-final appearances at the last two French Opens, although the 22-year-old did win the ATP Finals in London last year.
Stefanos Tsitsipas, 20, is perhaps the most promising youngster, reaching the Australian Open semi-final earlier this year and losing an epic fourth-round battle with Wawrinka at the French Open which went the full five sets.
But the shortage of players challenging the long-established elite is stark.
Women’s game has more players ready to step up
There is little doubt that the opportunity to watch Federer and Nadal do battle – as they did in the French Open semi-final – is the most alluring of prospects, but there are concerns as to who will pull in the audiences once they retire.
What’s more is that those who have come close to challenging the big three’s dominance, such as Murray, 32, Wawrinka, 34, and Cilic, are all also at the tail end of their careers.
The women’s game, by contrast, is in a very different state, as highlighted earlier this month by a Roland Garros final between 23-year-old Ashleigh Barty and 19-year-old Marketa Vondrousova, both making their first appearances in a slam final.
Barty, who stepped up her Wimbledon preparations by winning the Nature Valley Classic in Birmingham just over a week ago, is one of 10 current female players under 30 to have won a set in a grand slam final.
While Serena Williams dominated for a long spell, the emergence of the likes of Barty, Simona Halep, 27, Naomi Osaka, 21, and Sloane Stephens, 26, shows that the women’s game has players ready to step into the 37-year-old’s shoes.
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The men’s game, however, faces an all-the-more daunting prospect of replacing three of its most successful ever players.
For now, though, there is still time to enjoy them at their enduring best.