And it should come as no surprise that former UFC lightweight champion Khabib Nurmagomedov was the first name on his lips.
And of course, he couldn’t go without mentioning Royce Gracie as well.
The UFC Mount Rushmore is one of the most hotly-debated topics by MMA fans and pundits alike.
It’s inspired by the iconic American National Memorial sculpture, which features the carved heads of former US presidents George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln.
St-Pierre, 41, held the UFC welterweight championship from 2008 to 2013. He’s also a former middleweight champion – having famously come out of retirement to defeat Michael Bisping in November 2017.
GSP has been heavily linked with a comeback fight against fellow legend Khabib after retiring and named his potential would-be opponent – the legendary, all-conquering Dagestani wrestler – as his first pick for his UFC ‘Mount Rushmore’.
Speaking to Complex Sports, he said: “If you ask me who was the most dominating champion ever, then it’s Khabib Nurmagomedov, because he was undefeated, he probably never lost a round.
“Faced the most adversity, I got to say Jon Jones is there too.
“Who has the most flamboyance? I think Anderson Silva because he had some crazy highlight reels.
“Who has the biggest draw in terms of who raised the bar in terms of pay-per-views and awareness for the sport? Conor McGregor.
“Now I am going to go for my personal one. Who changed the game, who was the first one and did something that had never been done before? I think it’s Royce Gracie.”
And while he is now happily retired, St-Pierre admitted that he is still open to a grappling match with Nurmagomedov, as long as it’s not too competitive.
He told MMA News: “If it’s well-organised, if there’s some event that is well-organised, that is a novelty fight, something good, maybe, why not?
“I’m still in the entertainment world, I’m in great shape. I still train like a professional athlete. I still get it.
“Even some of the guys sometimes, they tell me, ‘Hey, are you preparing a comeback?’ I’m like, ‘No, I’m 40 years old. I’m done.’ I like to stay in there and keep my head in the game.”