Queiroz: Ronaldo was destined for greatness
Queiroz, who is now the Iran national team manager, coached Ronaldo during his time in charge of Portugal between 2008 and 2010, making the Real Madrid superstar captain of his country at the age of 23.
The 60-year-old also worked with Ronaldo during his two spells as assistant manager to Alex Ferguson at Manchester United before his compatriot left for Real in a then world record deal in 2009.
And Queiroz, who was at Old Trafford when Ronaldo arrived from Sporting Lisbon in 2003, had no doubt that the forward would establish himself as a modern-day great - even likening him to Chicago Bulls legend Jordan, who is widely considered to be the best basketball player in history.
"(Ronaldo is) the most complete player I have ever coached in my life," he said. "In terms of fitness, ability, technical, tactical.
"I can see in the last two years Cristiano growing up a lot, but he had everything.
"He had a little bit of Ronaldo (the Brazil legend, who Queiroz managed at Real Madrid in 2003-04), Figo - the speed, heading. He's fantastic at shooting with both feet, free-kicks, dribbling, passing.
"One day (at United), I don't remember when, I said he would be the Michael Jordan of football."
Queiroz, who will take Iran to their fourth FIFA World Cup finals next year, managed Ronaldo at the 2010 edition of the tournament, where Portugal were beaten in the last 16 by eventual winners Spain.
However, he expects the Portuguese - who has scored 29 goals in 23 appearances for Real this season - to have a major impact at Brazil 2014.
"I think he is more mature now, more experienced," Queiroz added.
"Four years in a player's career is a lot and it can make a huge difference.
"I think this will be his third appearance in terms of World Cup participation... so he will be able to manage the performance much easier."