Sometimes the simplest of truths is the hardest to digest, which is especially relevant in a sport where passions run high, and fan bases drive sporting rivalries off the sporting fields as much as the sportsmen confine their rivalries to the playing field.
In men's tennis, there is no bigger argument than the GOAT argument, which has been bandied about ad-nauseam and ad-infinitum by everyone from experts to anyone with even a passing interest in the sport. Despite what the numbers and facts (as will be discussed in this article) prove, it is still a wonder how people can even assert that one of Roger Federer or Rafael Nadal is the GOAT when the reality is crystal clear in the form of Novak Djokovic.
Number of Grand Slams: Comfort argument more than anything else
Roger Federer fans and admirers have long taken comfort in their minds through the idea that highest number of Grand Slams won automatically equals GOAT. They couldn't be more wrong. The mere fact that Federer has won 11 of his 20 Grand Slams against a field of players which included the likes of Marat Safin, Marcos Baghdatis, Fernando Gonzalez, Mark Philippoussis, and Andy Roddick should keep such thoughts in check. On the other hand, since the emergence of Djokovic and Nadal, Federer has a losing record against both Nadal and Djokovic in Grand Slam matches. He's down 9-3 to Nadal, where even if we exclude the French Open, Nadal would still have a lead of 4-3.
Novak Djokovic leads the head-to-head with Federer in Grand Slam matches by a margin of 9-5. On Federer's favored grass surface, Djokovic leads the head-to-head by 2-1.
Federer's fan-base always puts forward the Grand Slams argument when anointing him as the GOAT, but if we take a look at some real GOATs from other individual sports around the world, none of them would have losing records in major tournaments against their biggest rival(s). Case in point, Michael Phelps, Usain Bolt, even going as far back as Jahangir Khan (Look up his career stats from when dominated world squash events). None of these unquestionable GOATs in their respective sports have losing records against their closest rivals in major tournaments. Whenever Michael Phelps stepped into the pool at the Olympics, or whenever Usain "Lightning Bolted" his way on to the track at the Worlds or the Olympics, they ended up displaying their dominance against all their rivals.
Multi-Surface Expert: There's only one, and he's not from Spain or Switzerland
When considering someone as the greatest tennis player of all time, one would have to consider his record on all three different surfaces. Think of it a bit like cricket, where a batsman who can score in various different pitch conditions or a bowler who can utilize any kind of pitch to his advantage. If one is only good for scoring on flat pitches, the phrase, "flat-track bully" is quickly ascribed to that particular batsman.
In tennis, not only does Novak Djokovic own better head-to-head records against both Federer and Nadal but, but he also owns a much balanced record across all three surfaces. His winning record on hard-courts, clay-courts, and grass-courts is 84%, 79%, and 83% respectively. Federer's record is 84%, 76%, and 87%, respectively. However, that 87% on grass can be discounted a bit due to the beat-downs, he put on a watered-down field before the emergence of Nadal and Djokovic. Similarly, Nadal's 77%, 92%, and 78% records on the three surfaces, respectively show he's mostly dominant on clay.
Overall Record is Important, but strike rate is a more telling statistic
If one looks at overall winning percentages as well, its Djokovic and Nadal tied 83%, with Federer at 82%. But the real telling number is the strike-rate, i.e., titles won as a percentage of tournaments entered. And that number firmly puts Djokovic at the forefront, with a 31% strike rate, followed by Nadal (30%) and Federer (29%).
Add to this the fact that Djokovic's late emergence as a tennis professional has seen him compete in the Federer and Nadal era (should actually be called the Djokovic era). And yet, he has still managed to put up numbers better than those two rivals in terms of winning percentages and strike rates.
Miscellaneous, but important
Novak Djokovic has recently seemingly embarked on mission Novak 3.0 after his stellar 2011 and 2015-16 seasons. He's the only tennis player to have won back-to-back Grand Slams in men's tennis since 2011, and he's done it 6 times.
The world really seems to be at his feet at the moment, and for all those who argue that his game is predominantly based on putting the ball back in play need to monitor stats more closely. There is no better barometer in terms of aggressive play than Juan Martin del Potro (he of the Thor-like forehand), yet Djokovic ended up hitting more winners in the 2018 US Open final than del Potro and also managed to approach the net more than him with a better success rate in terms of points won. Yes, his game is based on a solid, steely resolve of a defense, but it is also based on a more strategic way of structuring points rather than just blindly going for winners.
The solid defense is even more impenetrable because his way of playing has made the return of serve the most important shot in tennis as against the serve itself. His exceptional returning ability creates a situation where his opponent doesn't have the same control over a point that he would have against any other tennis player.
Right now, he's sitting on a very probable opportunity to match Roger Federer in terms of year-end no. 1 finishes (currently trails 4-5), and also year-end-championships titles (currently trails 5-6).
Considering Djokovic's back-to-back Wimbledon-US Open wins (3rd time in his career), and his stellar numbers against not only the playing field but also his closest rivals. Therefore, there is no GOAT but Novak, and even Roger and Rafa fans know this in their heart of hearts.