Andy Murray is convinced Roger Federer, Novak Djokovic and Rafael Nadal are the greatest men's tennis players of all time - just don't ask him to put them in order.
The Scot might have had a stack more grand slam titles had it not been for the 'Big Three' of the modern era.
As well as his two Wimbledon triumphs, two Olympic golds and a 2012 US Open success, Murray has lost five major finals to Djokovic and three to Federer.
While Murray feels the likes of Bjorn Borg, John McEnroe and Jimmy Connors would be competitive in this age, he sees his direct rivals as the best there have ever been.
Murray told Djokovic in an Instagram Live chat on Friday: "The thing that's special now is you have three guys who are playing at the same time, so you can compare them because - I wrote it down - you played 55 times against Rafa and 50 times against Roger, and Roger and Rafa played 40 times.
"So you have that many matches between the best players in the biggest tournaments - so you actually don't have to compare the generations, and I think the best three players are playing now.
"It's difficult to judge it. We don't know what's going to happen in the future, so we don't know what everyone is going to finish on slam-wise and how many matches everyone will have played and won against each other."
Addressing Serbian star Djokovic, Murray said: "Also in this conversation, which is maybe different to other sports because we have the different surfaces, is that to me right now you have Rafa's record on clay nobody competes with, Roger's current record at Wimbledon is the best, and your record on hard courts is the best.
"So because we have these different surfaces, it's difficult, and when people ask me what's the toughest match in your career, who are the hardest guys to play against, I'd be like... I feel like I'm competing against the best hard-court player ever, I've competed against the best clay-court player ever and the best grass-court player ever, so for me it depends on the surface."
Federer has 20 grand slam singles titles, Nadal has 19 and Djokovic landed his 17th at the Australian Open at the start of this season. The campaign is now on hold due to the coronavirus pandemic.
Whenever tennis resumes, there will be a host of young players vying with the old guard for the biggest titles in the sport.
As Djokovic pointed out: "We are also not that young anymore.
"You have guys like Dominic Thiem, [Stefanos] Tsitsipas and [Alexander] Zverev, these guys they're maturing so quickly and they're ready - they're ready to get the grand slam titles and they're very close."
But Djokovic suspects it will be hard to budge the likes of himself, Federer and Nadal, as well as Murray and the Scot's fellow three-slam winner Stan Wawrinka.
He said: "When it comes to slams, I think it seems like we - including yourself and [Wawrinka] - you turn to another gear, because I think every next slam that keeps coming I feel more comfortable playing in. And I feel there's always even a bigger mental or emotional edge over the young guys coming in.
"Because you've played so many times you have the experience, you feel good in your own skin, it's really hard that anything really surprises you."