The 41-year-old scored no. 979 in Al Nassr's 2-1 win over Abha Club earlier this month, leaving just 21 goals before he marks his 1000th goal in a career that has spanned two decades.
Ronaldo scored his first for Sporting Lisbon in 2002, his 100th for Manchester United, his 500th for Real Madrid, his 700th for Portugal and his 979th for Al-Nassr as he fights to make history.
Ronaldo's 1,000 target is based on official senior competitive/international matches, unlike the likes of Pele, meaning he would become the first player to reach such a goal.
Speaking to Stake, Aguero backed Ronaldo to reach such a milestone in a feat he may complete before he turns 42 in February.
“I don’t know how much longer (he) will play, but he only needs another 21 goals. He can certainly do it. I don’t know what his plans are when the league season finishes or whether he’ll continue for another season. Scoring goals obviously isn’t easy, but he does it regularly.
“He’s like Leo: whenever he’s on the pitch, there’s a good chance he’ll score. If he stays for another season, I think he can achieve (1000 goals).
“I don’t know whether he intends to continue, but because he’s so close, he’ll probably try. If I were Cristiano, I’d think: "That’s it, I have no choice but to carry on for another year. "Then we’ll see whether it happens. If it doesn’t, it doesn’t matter.
“He should still be incredibly proud because that number of goals is almost impossible. The same applies to Leo. Their numbers are incomparable. I would carry on because I prefer round numbers. I don’t know whether he’s superstitious, what we call cábala in Argentina, or whether he dislikes odd numbers and wants to finish on an even number. I don’t know.”
Ronaldo's rival, Lionel Messi, reached 930 official career goals this week at the age of 39 and may beat his record if he continues to play until Ronaldo's current age.