Retired pro Rios was ranked as the best male player in the world for just six weeks in early 1998.
Although his spell at the top was short, that hasn’t stopped the Chilean from backing himself at his peak against the current world’s best.
Whilst speaking to Emol, Rios was asked if he could’ve beaten the serial Grand Slam winners – and he was surprisingly confident.
“I think so, I could have competed a lot,” he said.
“Now there are only four good ones, but before we were many: Sampras, Agassi, Muster, Ivanisevic, Chang, Martin, Enqvist and others.
“Before it was tougher on a competition level.”
Rios has defined the current crop as only having four ‘top’ players, those being Federer, Nadal, Djokovic and Andy Murray.
Those four have all had injury problems over recent years, but have also won 52 of the last 60 Grand Slam tournaments combined.
Rios, on the other hand, only ever reached a Grand Slam final once, losing in the 1998 Australian Open showpiece to Petr Korda.
Rios added: “My career was short and I could do less and maybe if I continued and if I prepared physically, I think I could have won a Grand Slam.”
The confident ex-pro hasn’t been shy of offering bold statements in the past.
Rios said in September: “If it’s Federer against Nadal, I’m motivated and I see it.
“I love Federer, I think he’s the best in history. He is a gentleman.
“It’s a hole in the crack, but I find off the court your life must be different.
“On the court, he’s like a women, he does not make any mistakes, doesn’t even spit.”
Nadal, Federer, Djokovic and Murray will all be preparing for the Australian Open which takes places from January 12-21, with Federer looking to keep his crown.