Djokovic has been on a tear since the middle of last summer when he hit peak form during the grass season, won the 2018 Wimbledon Championships, and then took his hot streak into the hard court season when he claimed the Cincinnati Masters, the US Open, and the Shanghai Masters titles in a three month span.
Should he win the second French Open of his career at Roland Garros this year, then he'll have triumphed in four consecutive Grand Slam tournaments in tennis something that only two other athletes other than himself have ever achieved in the entire history of the men's singles category.
He has done this once before, known as the Nole Slam, when he won his first French Open title in 2016, having won all majors in the previous year.
Federer told Sport 360 that this is "super impressive," but he then downplayed the achievement when he said it is actually easier to accomplish this in the modern era than when the former great Don Budge won six Slams in a row between 1937 and 1938 or when Rod Laver completed Calendar Slams in 1962 and 1969.
"There is no secret that nowadays it's easier to do than maybe before then. It's just that the surfaces play more even today, more equal. Back in the day you had really fast grass courts to extremely slow clay courts."
Federer then referenced the former world number one tennis player Bjorn Borg, who won 11 Grand Slam titles six at the French Open and five consecutive majors at Wimbledon in the mid to late 1970s and early 1980s.
"The difference was just so extreme that it was hard to do what Borg did you know, winning back-to-back French Opens [and] Wimbledons because the game was so different. You really had to serve and volley on grass," Federer said. "Today you can not serve and volley once on grass and win Wimbledon."
Though Federer has won 20 Grand Slam titles he has never held all four majors at the same time, though he has come close. Rafael Nadal, too, has 17 Grand Slam titles but has never won each major consecutively.
"Thats what I'm saying, it could happen more frequently. Thats what were seeing. I won three, made the finals once. Rafa, I think he was close many times. Novak has been extremely close, has done it once, now maybe going for another one.
"So it shows that it is more possible today," Federer said, before eventually praising Djokovic. "But the feat, still regardless of the conditions are easier, is still and would be an unbelievable one. Credit to him."
Federer and Djokovic are currently in Florida for the 2019 Miami Open.
They are both in the second round of the competition. Djokovic will face the winner of Bernard Tomic and Thiago Monteiro's first round match, while Federer will take on either Radu Albot or Matthew Ebden.
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