I learned so much during my time at United. Sharing a dressing room with Paul Scholes, Cristiano Ronaldo, Wayne Rooney, Ruud van Nistelrooy, and Ryan Giggs at such a young age was an amazing experience. I didn't play as much as I would have liked, but it was a master's degree in development both as a player and a person.
During the Sir Alex Ferguson years, you would see all those great players - Roy Keane, Paul Scholes, David Beckham, Ryan Giggs, Jaap Stam, Ruud van Nistelrooy and Cristiano Ronaldo, to name just a few - and you'd quickly realise why Old Trafford had an aura like nowhere else.
Rooney is one of the best players in the world and I love watching him play. But if you had to pick out only one, then for their history and for all that they have achieved it would have to be Paul Scholes or Ryan Giggs. They are two shining examples for any player.
In my years at United, I witnessed some signings who, over their careers, transformed the fortunes of the team. From Eric Cantona, when I was an apprentice, to Dwight Yorke, Ruud van Nistelrooy, and Wayne Rooney. These were great footballers who became great United players.
For me, Paul Scholes is on the same level as Ronaldo. The real Ronaldo, not Cristiano. I always thought he was a great player but after I played alongside him I realised he was Manchester United's greatest player of all time. He did his talking on the pitch which I respected most.
When I played for Stuttgart, I met Manchester United and Chelsea. With United, I immediately think of the duels with Ryan Giggs and Paul Scholes and with Chelsea, it was John Terry. Those players are symbols of their clubs and the success they had at that time.
What do you think of Manchester Uniteds three Rs - Rooney, Ronaldo and van Nistelrooy?
I liked the generation of Paul Scholes and Ryan Giggs, who I admired. I was a little bit jealous of Karel Poborsky who played in Manchester and experienced great matches. I know he still feels that love.
Everyone went crazy over Wayne Rooney, but I get more excited by Cristiano Ronaldo.
As a private person I think I am now totally different from Ruud van Nistelrooy the footballer.
During my time playing for England we had Wayne Rooney, David Beckham, Michael Owen, Steven Gerrard, Frank Lampard, Paul Scholes. They were world-class players playing for Chelsea, Man United, Liverpool, Arsenal, all legends of the game.
When I was a kid and my dad was playing for Man United, I used to stand behind the goal watching Eric Cantona, David Beckham, Paul Scholes, Mark Hughes, Andrei Kanchelskis, Ryan Giggs... and I used to try to save all their shots that went wide, imagining I was deciding the title for United.
The likes of Wayne Rooney, Dimitar Berbatov, Michael Owen, and Ryan Giggs - I can see it live every day. I don't have to sit in front of a TV to study it.
I saw United matches on TV as a kid in Sao Paulo. I loved watching Ruud van Nistelrooy. He was a hero for me because of the way he scored goals in all competitions.
Growing up, Wayne Rooney and Cristiano Ronaldo were the players I looked up to - and Carlos Tevez when he was at the club.
As a goalkeeper, I needed good players around me. I needed Nemanja Vidic, Cristiano Ronaldo, and Wayne Rooney. It's the same as a CEO.
It would not be honest if I did a review, because I've worked with Leo Messi, whom I consider the best player I've seen. I cannot comment or compare with Cristiano Ronaldo because I have not worked with him. That is not to say that I do not have as much respect for Cristiano as a footballer.