Eight-time Grand Slam-winner Andre Agassi said tennis was witnessing a "golden age" and that Novak Djokovic, Roger Federer and Rafael Nadal were arguably the best the sport had seen.
Agassi, 42, speaking on Friday during his first visit to the Australian Open since he retired in 2006, joked that the only way he could have beaten Djokovic, the world number one, would have been to pick a fight with him.
"Let's see. I would have probably gotten in a fight with him in the locker room before the match. I might have had a chance, maybe there," Agassi said, adding that he was amazed at how standards had soared.
"It's been amazing watching the standard continually sort of get better. You wonder how it's possible, you know, to continue at that sort of rate.
"I mean, what Federer did when he came and when I said goodbye, a lot had to do with what I knew was untouchable.
"It's just a different standard of tennis. It's different rules of engagement when guys can do what these guys can do. I don't recognise it from a standpoint of strategy, because I counted on getting somebody behind in a point and then slowly smothering them.
"But nobody's behind in a point. You never know when they're behind in a point. That would have eliminated any ability I had to move forward in the court.
"Means I would have had to be a different player, would've had to have a different body. It means the game has gotten a lot better."
Since Agassi retired, Federer has outstripped Pete Sampras to reach a record 17 major titles, including a career Grand Slam. Nadal has totted up 11 and Djokovic, 25, has been the dominant player of the past two seasons.
"You know, Fed raised it; Nadal matched and raised it; Djokovic, for that intense little period of time, even raised it," Agassi said.
"It seemed like last year settled down a bit, and now all of a sudden (Andy) Murray is in the equation of where is he going to go.
"But when I see those top three guys, I see what history will say is the golden age of tennis. You're talking about arguably the three best guys.
"Djokovic will still need some distance to cover, but best of all time, if you're having that discussion in the same generation, it's remarkable."