Novak Djokovic may well have already established himself as the GOAT of men’s tennis, but his former rival Roger Federer believes the 36-year-old Serb can still win Grand Slam titles “for a long time.”

Djokovic just won a men’s record 23rd major singles title at the French Open, surpassing his longtime rival Rafael Nadal’s 22 and tying Serena Williams at 23. Only Margaret Court is ahead of Djokovic at 24.

“I thought what Novak did is incredible,” Federer, speaking on a tennis court back in southeast London after retiring last year, said according to British reporter James Gray.

“Honestly, it’s great for tennis, great for sports when tennis writes its own history and keeps on adding to it like we’ve seen with Serena Williams as well, Rafa then myself and now with Novak.

“It’s a great time in tennis to be a fan as well, but also a player.

“I remember when I came on tour, and Pete Sampras reached 14 we thought ‘Okay, that one is gonna stay forever’. Then I went to 15, I eventually ended up at 17, and then we pushed each other to 20 – I don’t remember who was first – and then Rafa pushed it to 22.

“Then now Novak pushed it to 23 and he looks like he’s gonna keep on doing that for a long time still to come, which is great. And I wish him all the best.

“I think also the way he’s doing it still – he isn’t the youngest anymore, we forget. He looks young and he does it in a young way, but it’s not easy, and I thought it was an amazing victory. So I couldn’t have been more happy.”

It wasn’t too long ago that Federer was considered the GOAT with his 20 Slams. At the end of 2010, he had 16 majors to nine for Nadal and one for Djokovic. By 2020, Nadal and Federer were tied at 20 with Djokovic coming on fast with 17.

In the 2019 Wimbledon final, Federer famously held double-match point on Djokovic in a match that would’ve given Federer a 21st major title and left Djokovic with 15 instead of 16. Instead, Djokovic fought off both match points on Federer’s serve and went on to win in a dramatic fifth-set tiebreak.

Now Djokovic has 23 and his once again halfway to the first calendar Slam since Rod Laver in 1969. He will attempt to win the third leg starting next month at Wimbledon, where Federer said he will be for several days.

Jim Courier, for one, agrees with Federer that the surpremely conditioned Djokovic can contend for major titles for several years to come.

“I don’t think Djokovic is going anywhere,” Jim Courier said during the semifinals. “He’s got Tom Brady mentality. He still wants to be winning these things when he’s 40.”