Ronaldo is regarded as one of the best players of all-time, having won every possible award in football and scoring more than 700 goals so far in his career.
The former Manchester United forward has seen a slight decline in his astronomical numbers in recent seasons, but has recently signaled his intention to keep playing at the highest level for many years to come.
Speaking at a media event in Russia, Nurmagomedov was asked why Ronaldo “seems not to want to retire”.
The Russian, who is regarded as high as Ronaldo in his respective sport admitted that, it is hard to ‘leave something you have done your whole life.’
"It's hard to leave something you've done your whole life,” the 31-year-old said.
"But it doesn't matter whether you want to [retire] or not. The time will come when if you don't leave the sport, the sport will leave you.”
"If you don't leave at the right time, you'll be left behind as there'll be new champions, younger, hungrier, more motivated guys.”
“You won't have the same motivation and hunger you've had at the beginning of your career towards its end".
He added: "Nobody will be around forever, so it's important to leave at the right time.
"How old is he [Ronaldo}? 34? At 35 he won't have the same conditioning and reaction time. It doesn't matter if it's Cristiano or Khabib, people will come and take your place.”
"My advice to him, and to me as well, is to leave at the right time".