Of course, the trio of poster boys for the ‘mature’ men in this sport have topped the tables for years—indeed well over a decade.
Between them, Novak Djokovic, Rafael Nadal and Roger Federer, ranging in age from 31 to 37, and ranked Nos1, 2 and 3, have won 50 of the last 60 Majors dating back 15 years. Even after extended injury breaks, the same three have returned as strong as before: In the last two years, they have won all eight Majors and 10 of the 17 Masters. And they will have held the No1 ranking since last autumn.
In short, they all continue to defy their ages.
Federer became the oldest No1 with the Rotterdam title in February, shortly after winning his third Major in just over a year, his 20th overall, among them a record eighth Wimbledon title and a record-equalling sixth Australian title.
Nadal opened up a lead in Masters titles to 33, and won an extraordinary 11th French Open title—a record in any Major—as well as becoming the third oldest No1.
Djokovic joined his two biggest rivals in equalling the former Pete Sampras record of 14 Majors—what seemed, 15 years back, an insurmountable tally. In reclaiming the No1 this week, he became the first to come from outside the top 20 to reach No1 in a single season since 2000, and he has every chance of drawing level with Nadal on 33 Masters titles by the conclusion of the Paris-Bercy tournament.
Such dominance has made it hard for the rest to reach the heights. Majors and Masters have been hard to come by, and the No1 ranking a near-impossible target—except for Andy Murray, who got his reward in 2016 after 78-match-wins, nine titles and a third Major title.
However, age has proved to be no barrier to a number of men who have continued to build on big ambitions into their 30s.
Juan Martin del Potro has battled more than most with injury, repeated surgery, and numerous comebacks. He won his only Major almost a decade ago, but it took another nine years and 21 titles before he won his first Masters title, in Indian Wells this spring.
And after making No4 in the ranks in 2010, and again in 2014, he reached a career-high No3 this August and qualified for the Nitto ATP Finals for the first time since 2013. That he fell and fractured his patella in Shanghai was an injury blow he did not deserve, but whether or not he plays in London, he has shown he will not be deterred by the years.
Just as significant has been the trajectory of 33-year-old John Isner, who also became a debutant Masters champion in Miami this year. Until this year, he had only reached the third round at Wimbledon in nine previous visits: This time, he made his first ever Major semi-final, went on to make the quarters at the US Open, and reached a career-high No8.
Perhaps surprisingly, for a player of 33 who had flirted with the top 10 before, Isner has never qualified for the end-of-year finale, and although he is not yet there this year—and was hampered by a loss to Karen Khachanov in the third round of the Paris Masters—he does still have a chance of joining the elite eight, and at the very least of taking an ‘alternate’ place this year.
Then there is Kevin Anderson who, at the age of 32, has ticked off career firsts throughout the last year like a player a decade younger. After making his first Major final in New York last September, he made his second in Wimbledon this year and scored his first two Masters semi-finals.
He then capped his best ever season in Austria last month with his first ATP500 title, with victory over Kei Nishikori, 6-3, 7-6(3). And that represented another huge step in Anderson’s tennis career: It sealed his first qualification for the season finale in London, making him the fourth oldest first-time qualifier.
For Anderson, then, meeting Nishikori again in the third round of the Rolex Paris Masters this week had limited impact, but it had significance for the considerably younger Dominic Thiem. The young Austrian is on the verge of qualifying for London, having reached the quarter-finals in Paris Bercy via a tough victory over Borna Coric, 6-7(3), 6-2, 7-5. It had significance for Nishikori too: every point is valuable, and the Japanese man added 90 to his cause with a straight-sets win.
Marin Cilic is lined up to be the sixth over-30 to make up the elite eight in London. The US Open champion back in 2014, Cilic has been enjoying his best 18 months since then, capped by two Major finals at Wimbledon and the Australian Open, plus three Masters semis and three Masters quarters through the same period. And his successes have propelled him to a career-high No3. Currently No7 in the Race, he will target a new milestone on his fourth visit to London: to advance beyond the round-robin stage for the first time.
And what of the over-30s poster boys? No surprise there as the quarter-finals took shape in Paris.
Federer advanced to the quarters by beating 31-year-old Fabio Fognini—another man who has edged close to London qualification for the first time after one his best seasons—6-4, 6-3. And Djokovic took a swift step onwards after Damir Dzumhur was forced to retire at 6-1, 2-1 down.
1. Novak Djokovic 
2. Rafael Nadal [participation in London unconfirmed] 
3. Roger Federer 
4. Juan Martin del Potro [participation in London unconfirmed] 
5. Alexander Zverev 
6. Kevin Anderson 
Still in the Race: 2 plus 2 alternates
7. Marin Cilic 
8. Dominic Thiem 
9. Kei Nishikori 
10. John Isner 
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BIOGRAPHY: Ethan Hazard
BIOGRAPHY: Daniel Sturridge