It was at the Arsenal training ground when Barcelona came to work, before playing in a Champions League final at Wembley. I stayed behind, watching from a window — I wanted to see what I could learn about them.
Perfect pitches, across 150 acres, stretching out as far as the eye could see, but Pep Guardiola chose the smallest of them, right next to the building. It was an area normally reserved for goalkeepers but he set up what appeared to be an 11-a-side game in a cramped area.
A fast session of keep-ball followed. Pop-pop-pop the ball went. Immaculate control, pass it quickly before you are closed down. Pop-pop-pop.
He then took to a second pitch, a larger pitch. A signal from him and his players sprinted over for a possession-based session.
Another signal and it was shooting practice. He was grabbing players by their shirts, even Lionel Messi. Pep and his coaching staff were roughing up the forwards, creating resistance as they were trying to score. It was a privilege to watch him work up close.
It occurred to me how enormous Wembley must have felt after the tight space he had used at our training base. And it worked, as Barca took Manchester United to the cleaners in that 2011 final.
Since coming here in 2016, this is the man who has transformed English football. He has created the best team we have seen on these islands with his coaching and methods of play.
I recently commented on Match of the Day about Manchester City’s five trophies, all lined up, a show of dominance and force. If I were still competing against them, I might like to stumble and accidentally knock one over.
But I do like what they have created. The way City’s players celebrated together with their manager after winning at Newcastle in their last game. A band of brothers, a team united.
A symbol of their togetherness — and there he was. Pep, right in the middle of it. I liked that. It looked pure. If I am picking my greatest manager, he has to be No 1. Then there are Sir Alex Ferguson, Arsene Wenger, Jose Mourinho and Jurgen Klopp.
I am not listing them one to five. There are four who are very close — and then Guardiola. Critics might say he has the big budget and the best players, but he is using it to a maximum.
His style is rippling through English football. Teams from here to the far reaches of the land, even in Sunday pub leagues, are playing out from the back. Beat the press, keep the ball, use it quickly. The Guardiola Effect. It will remain long in the memory.
I rewatched City’s last game against Newcastle for this article. Remember, in this game, with City trailing 2-1, two substitutes scored to win the three points. Two changes Guardiola made.
When he was losing, he didn’t panic. He looked around at his bench and could see Kevin De Bruyne. His best player, just back from a bad injury. Did he bring him on at half-time? No. He waited. He waited. It might well have been driving him crazy but he timed the decision perfectly.
Within five minutes, De Bruyne had scored and then he laid on the winner for Oscar Bobb. The pass was so good, it was like a handwritten invitation to score.
I have a football tactics whiteboard at home and I have taken out my chess set alongside it on the kitchen table to try to work out the movements of Guardiola’s team. When he was in America on a year’s sabbatical, he spent time with chess grandmaster Garry Kasparov. I imagine Pep using that time to learn.
In chess, as with football, you have to control the board. Who are the rooks in the City team moving vertically or horizontally through unoccupied squares? Who is their king? De Bruyne, probably. Or Erling Haaland? Bernardo Silva? Ederson?
In a theatre of noise, Guardiola is always calculating his next move into space. It is how he continues to redefine the boundaries, it is how he stays No 1.
It takes me back to the training pitch at Arsenal that day. We are seeing something special. We must appreciate it for he won’t be in the Premier League for ever.
Pep Guardiola: Chasing Perfection - Tonight: BBC1, 10.40pm