When one of the two happens to just win a slam a day or two ago, the GOAT sentiment rises and then dissipates just as quickly.
Federer is widely regarded as the best Tennis player of all time based not just on having won more grand slams but also having won Wimbledon - which is the crown jewel of men's Tennis - more than anyone. Here are a few more items that will be evaluated when comparing them.
- Most weeks at the number one player in the world - 309 (Nadal is 6th at 177)
- Most consecutive weeks at #1 - 237 (Nadal is 11th at 56)
- Most ATP singles titles ever: Here Federer is 2nd behind Connors. (Nadal is 4th)
- Most ATP singles finals: Roger is 2nd behind Connors, Rafa is 4th
- Most Slams 20 (Nadal 17)
- Most Slam Finals 30 (Nadal 24)
- Most Slam match wins 332 (Nadal is 3rd behind Djokovic at 237)
- All time match winning % on hard courts (Roger #1 - Rafa#11)
- All time match winning % on clay (Rafa #1 - Roger not in the top 10)
- All time match winning % on grass (Roger #2 - Rafa not in the top 10)
- Career match wins v top 10 opponents - Roger #1 at 214, Rafa #4 at 159
So the big elephant in the room then is the head to head matchups where Nadal is ahead. But it has to be said that Federer has won the last five against Nadal, which has closed the gap significantly to 15-23. All of these wins have come as Federer has been in his mid 30s which isn't particularly flattering towards Rafa's perceived dominance of Roger, since the latter is nearly 5 years younger.
So all things said, in order to be widely considered the GOAT (as opposed to narrowly by his fan boys), Nadal will have to not only catch Federer on slams, but also catch him on at least two or more of the above stats where Roger is currently ahead quite comfortably. Even under the best of conditions, the likelihood that this will happen is extremely implausible.