In 2008, Cristiano Ronaldo scored 42 goals to help Manchester United to the Champions League and Premier League double. It was a performance that earned him the Ballon D'Or and he was comfortably the best player in the Premier League. In the eyes of coach Alex Ferguson though, he wasn't quite the finished article.
Even then -- he had it all. Pace, the desire to score, the ability to beat defenders in one-on-one situations. But his performances at Real Madrid have raised the bar so high that Ferguson now believes that the Portuguese skipper is a complete player.
In January 2013, Ferguson told Inside United: "Maturity brings many things. When I went to see them play against City, some of his decision-making in terms of passing was brilliant. One-touch passing, good crosses.
"In the six years we had him, you just saw his game grow all the time, and he was a fantastic player. Now you see the complete player. His decision-making, his maturity, his experience, plus all the great skills he has got, they all make him the complete player."
And what has that complete player done to his opponents? A quick analysis of his performances at Real Madrid vis-a-vis his time at Manchester United indicate that his growth hasn't stopped at all.
In 287 appearances for Manchester United, Ronaldo scored 116 goals and had 60 assists. In just 179 matches for Real Madrid, Ronaldo has scored 182 goals and has 54 assists. It is a strike-rate that is downright scary.
Some might say that a lot of his goals have come against weak opposition in the La Liga. But then he hasn't done too badly in the Champions League, which features the best teams from across Europe.
In 52 Champions League games for United, he scored 15 goals. He has almost managed to double that number for Madrid -- 29 goals in just 34 games.
If you stick to just league numbers, in 196 games for United, he got 84 goals and had 47 assists. For Madrid, he is averaging more than a goal a game -- 136 goals from 123 games, with 42 assists.
Whichever way you look at it -- the numbers are scary. But what makes him so good?
According to Gary Neville, the former Manchester United defender, his ability to zero in on the weak links in the defence and prey on their frailties makes him very dangerous.
“Ronaldo is a bully. He bullies the weakest defender. He does it all the time," Neville told The Sun. “He did it to Manchester City against Maicon. He will play on the left wing.
"If he can’t get on the ball he will play centre-forward, midfield, right wing.”
It makes him a difficult man to mark. He is probably one of the few players in the world who has the freedom to roam all over the pitch and it means he can also draw others players out of formation and create gaps where there were none.
It is a gamble every team has to take. Do they let him roam free or do they try and shackle him? Either which way, there are risks involved. Messi has a great record as well but you don't expect him to suddenly unleash a shot from 30 yards out -- with Ronaldo you are never sure. He can score from open play, from free kicks and the outrageous is never beyond him.
Surely, there are days when Ferguson thinks about Ronaldo and wonders about how he let this monster get away. As good as Robin Van Persie, as clinical as he is... he is no Ronaldo.
So try as United might, on Wednesday, Ronaldo will create chances... plenty of them and somehow they will hope that he'll miss most of them. This will be Cristiano Ronaldo’s first encounter against his old side since leaving for a world record £80million in the summer of 2009 -- and he may have his flaws but he sure knows how to pick his moments to shine.
And in that moment, expect him to look at Rooney and wink because that's who he is.