Roger Federer ranks among sporting greats such as Michael Jordan, Tiger Woods and Tom Brady.
That was the message from 2013 Wimbledon champion Marion Bartoli, who hailed Federer after he announced his appearance at September's Laver Cup would be his last in professional sport.
The 41-year-old won 20 grand slam titles across a legendary 24-year career, only Novak Djokovic (21) and Rafael Nadal (22) can boast more major crowns in men's tennis.
Federer has also won more men's singles main draw matches in grand slam tournaments than any other player in the Open Era (369), leaving behind a magnificent legacy as he prepares to step away from the court.
Bartoli has experienced retirement herself, having called quits on her career after a failed comeback from injury in 2018, and asked by Stats Perform whether Federer was a GOAT – greatest of all-time – Bartoli said: "Yes, he is very much in there – absolutely.
"Michael Jordan, Kobe Bryant, LeBron James, Tiger Woods, Tom Brady, they are people that transcend their sports – they are icons.
"You go in the streets, you say Roger Federer. I'm in Dubai right now [and if] you say 'Roger Federer' everyone would know who he is. And the same for LeBron and Michael Jordan.
"When you transcend your sport and you become an icon and everyone knows who you are, that's when you know you have been one of the greatest of all time across every sport.
"Same for Serena [Williams], you can put Novak and Rafa in there as well. But it's just that amount of fame and that amount of inspiring [the next] generation."
Having spent 237 consecutive weeks ranked as number one, Federer holds the record for the longest such streak in men's singles history after a four-and-a-half-year spell at the summit.
Federer was also present in the top 10 of the men's singles rankings for 750 weeks, an unmatched number for a male player since the rankings were first published in 1973.
Regardless of Federer trailing Djokovic and Nadal for grand slam titles, Bartoli believes the Swiss remains the best of the trio due to his elegant playing style.
"It's very much depending on your own taste in a way. If you like beautiful, elegant, smooth tennis you have to go for Roger Federer," she added.
"Now obviously with Novak having 21 and Rafa having 22 grand slams, if we speak numbers only then you have two players on top of him.
"But I think it's very much a debate because it depends on the style of play you like and, that said, I absolutely love to see Novak play and win.
"I absolutely loved to see Rafa winning again at Roland Garros this year, I think it was one of the most incredible sports achievements that you can possibly witness.
"But in terms of game style, and the way he has revolutionised tennis, I think Roger was the first one. And then they pushed each other to new heights and I think that was really special to see."
While many youngsters look to emulate Federer, Djokovic and Nadal, Bartoli highlighted the importance of Pete Sampras and Andre Agassi, too.
"You can tell how much impact a player [has] when you see a new generation trying to copy your style. I think Pete Sampras had that impact as well as Andre Agassi on the generation of Roger, Rafa and Novak," she continued.
"Roger has had that impact on the new generation with Carlos Alcaraz. So that's why I say that he was really the first one to elevate the game to another level because he brought that dimension of his forehand when he was really almost able to play the ball wherever he wanted.
"I always remember that sentence from Andre Agassi, when he started to play against Roger saying, 'well, I never felt against anybody that I had to play on a 20-centimetre square because that's the only safe spot I can play, which is deep to Roger's back. If I play anywhere, he will take the game away from me'. [Federer] was the first one to [do that] and then obviously Rafa and Novak arrived and sought to change that and they pushed each other to new heights.
"When you have the pinnacle of the 2008 Wimbledon final and all those matches in between them that was just beyond epic for me."