Speaking back in April 2015, Sir Alex Ferguson said: "People say who is the best player in the world? And plenty of people quite rightly say Lionel Messi — you can't dispute that opinion.
"But Cristiano Ronaldo could play for Millwall, Queens Park Rangers, Doncaster Rovers... anyone, and score a hat-trick in a game. I'm not sure Messi could do it.
"Ronaldo's got two feet, he's quick, great in the air, he's brave — Messi is brave, of course. I think Messi is a Barcelona [type] player."
Messi is yet to score a goal in three games across all competitions for Paris Saint-Germain while Ronaldo has found the net four times in three games for Manchester United.
The Argentine actually threw a tantrum last week, refusing to shake manager's Mauricio Pochettino's hand after being substituted. PSG went on to score the winning goal without the 34-year-old.