Fretting over Fedal: Are we prepared for the day when Federer and Nadal stop enthralling the world with their magic?

Things can change quickly in the world of sport. You know how it is; you remain on edge even when your team's best batsmen are in the middle of a 100-run partnership, because you know just one wicket can derail the whole innings. You don't celebrate when your favourite gets an early break, because you know he might get broken right back.

But that kind of obsessive caution, that fear of change, is thrown out of the window when it comes to the careers of star athletes. A player who is winning titles is expected to keep soaring high above the field forever. And a player who is struggling for form is relegated to the also-rans' bin faster than a John Isner serve.

In 2013, scores of people kept questioning why Roger Federer hadn't announced his retirement yet. He failed to reach a Grand Slam final all year, won just one tiny tournament (at his beloved Halle), and suffered losses to players like Daniel Brands and Federico Delbonis. The Swiss just about qualified for the World Tour Finals, but even when he got there he looked like a pale shadow of his all-conquering self from years past.

In 2015, people asked the same question of Rafael Nadal. He lost to Fabio Fognini at the US Open despite leading by two sets and a break, struggled to string together more than three wins anywhere, and horror of horrors, lost a match at Roland Garros. The Spaniard seemed a step slower and an idea behind, and it was hard to imagine what, if anything, could ignite his resurgence.

Today, as you've probably heard, Nadal and Federer are No. 1 and No. 2 respectively in the year-to-date ATP rankings, having swept all the Slams played in 2017 so far. They have somehow turned the clock back to 2006-2008 - when the ATP field was referred to as 'Fedal and the rest'.

Nadal dropped just 35 games - the least of his career and second least by any player in history - on his way to the French Open title. Federer won Wimbledon without the loss of a single set - the first time he's achieved that feat at SW19. The ridiculousness of the numbers have made us wonder whether Federer and Nadal, instead of slowly fading into oblivion, are playing better than they did at their respective peaks.

They are running circles around their opponents, and their footwork looks more like a dance than a battle charge. They are ruthless and resplendent, and they are expected to remain that way. The refrain has changed from "When are you going to retire?" to "Never retire, legend."

But as I keep seeing those 'never retire' exhortations all over the internet, a chilling fear creeps up on me.

It is tempting to anoint Federer and Nadal as 'ageless wonders', and to expect them to keep ruling the courts till eternity. But the reality is that Nadal is 31, Federer is 36, and neither of them is getting any younger. Sooner or later they will start playing like their age.

Federer has already given us a glimpse of what that will look like - in both 2013 and 2016. Nadal's physical frailties in 2015 were less obvious, but they were present alright. The two titans may have found ways to erase the doubts in 2017, but they will be hard-pressed to keep doing that in 2018 and beyond.

And as sacrilegious as this may sound, even their 2017 play has shown signs of terminal decline.

Both Federer and Nadal are undeniably slower on the court today than they were in their primes. They are more vulnerable to big hitters than before. And they also make more errors off their biggest strength (the forehand) now than they used to.

Sure, they have both improved their weaker wing beyond recognition, but the backhand is not the shot that pays the bills. Or to be more precise, it is not the shot that cashes in the pension.

The other, considerably less pleasant side to this conversation, is the quality of competition they have faced this year. Andy Murray is the World No. 1, but right now he's not a patch on the player he was six months ago. Djokovic has been suffering from injuries and burnout, and it's anybody's guess when he'll be back to winning ways. #NextGen hasn't nextgen-ed yet, with the possible exception of Alexander Zverev - and even he has failed to reach a Slam quarterfinal so far.

This is not a knock on either Federer or Nadal; they can only play the opponents who show up on the court. Moreover, the way Djokovic has been playing this year, he would've probably been turned inside out if he had run into either player at the Slams (Nadal actually did turn Djokovic inside out the only time they met this year, at the Madrid Masters). But the fact remains that the one consistent challenger who had been depriving Federer and Nadal of glory the last few years, has been practically missing in 2017.

Of the four defeats that Federer faced at the Slams before this year's Australian Open, three came at the hands of Djokovic. And the last time Nadal lost at the French Open, his opponent was...Djokovic.

I have a hard time imagining anyone other than Djokovic stopping Federer's march to the 2014 and 2015 Wimbledon titles, or even the 2015 US Open. And Robin Soderling would have continued to be a big name in trivia quizzes if not for Djokovic's all-conquering 2015 season.

What if Federer and Nadal had been playing just as well from 2014 to 2016 as they are this year, only for their brilliance to be repeatedly masked by Djokovic's dominance?

There is a counterpoint to that. In 2017, both Federer and Nadal have been better against opponents who've had their measure in the recent past. The likes of Fabio Fognini, Milos Raonic and Marin Cilic have been far less troubling for Fedal this year than they were from 2014 to 2016. So maybe it's not just about Djokovic.

Either way, Federer and Nadal never gave any indication they were ready to throw in the towel when they were being given the runaround by the Serb. They never stopped fighting, never stopped trying to find the hidden strength within them that could crack the seemingly unbreakable wall. They didn't succeed, but why weren't we more fascinated by their heroic struggle?

When a legendary athlete starts aging, the logical thing for everyone else to do is to enjoy the athlete's play as long as they can, irrespective of results. But recent evidence suggests that we humans are incapable of that; we don't like it when our heroes lose, no matter how hard they fight. We want them to remain forever flawless, forever fantastic.

That Fedal have been flawless and fantastic in 2017 is to our immense privilege. It's often been said that the current generation of tennis fans is lucky to be alive during the time of Federer and Nadal. We'll have to think of a new term to describe our unbelievably good fortune now that the two have decided to stretch the boundaries of their greatness beyond any recorded human limits.

Luck is not endless though, and sooner or later we'll run out of it. Everything looks rosy and beautiful now, but it can all go up in a puff of smoke. If not Djokovic, some other player will come along and expose their age. Or they could be brought down even in the absence of any worthy opponent.

Federer could suddenly stop bamboozling his opponents with those insane drop shots, because his wrist doesn't twist so effortlessly anymore. Nadal could suddenly stop curling those banana forehands past bemused net-rushers, because his arm doesn't rotate so forcefully anymore. And then, the world will look a little less exciting, a little less spectacular.

Are we prepared for that? Are we ready to face the consequences of change, the only constant of the sporting world?

The Fedal Dance is not over yet. But I dread the day that it will be, like I have never dreaded anything in my life before.