Marcelo Bielsa was the coach who discovered Mauricio Pochettino, setting him on the path to becoming an Argentina international.
Pochettino earned all 20 of his caps under Bielsa, also playing for him at Newell's Old Boys and Espanyol.
Speaking ahead of Monday Night Football, he explained what makes Bielsa such a demanding coach, provided some insight into the unique detail of his work that put him two decades ahead of everyone else, and offered his view on whether Leeds can keep up their high-tempo approach…
On his early memories of Bielsa…
"The most important thing that everybody needs to know is that he is a very special man. He is a very different character and a very different coach who believes in a different way to play, his own method that he created to train.
"It is difficult to adapt to him. But for me it is very difficult to talk about him because my relationship with him began when I was 13 when I arrived at Newell's Old Boys. When you are a kid trying to translate his ideas to the spectators it is tough.
"I remember my first day on the training ground, playing 11 versus 11, I was desperate to play. I was 13, that is all you want to do. He told me that I would play as a striker, like Harry Kane. I said, 'No, I am a centre-back'. He told me that his scouts told him I was a striker.
"I told him that was because it was a small town and I was the best player. You play in every position if you are the best player. He said, 'OK, you are going to play as a centre-back'.
"After five minutes, he told me to sit next to him. He said, 'Mauricio, you are going to be a Newell's Old Boys player. Now go to take a shower.' I said, 'Why do I need to take a shower, I have only been playing five minutes.' He said, 'No, go to the office and then go back to your town and tell your dad that you are going to play for Newell's Old Boys.'
"For a kid aged 13, that explains how he was and how he is. He had this unbelievable intuition, perception. So clever. He had a different brain to all of the people that I coach."
On man-to-man marking under Bielsa…
"We need to split the two aspects. When you go to press high you have to take a risk if you want to be successful. It is about attitude, of course, aptitude, but attitude. It is about taking risks and playing high with your defensive line. If you recover the ball you can attack quickly.
"Whenever a coach prepares his team to press high, it is about being successful and recovering the ball as close as you can [to the opposition goal] to have the capacity to create a chance.
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"But it is also about how you are going to behave if they break your first pressure. Are you going to follow man-to-man or are you going to behave in a zonal organisation? That it is how it is going to change.
"Sometimes when the opponent breaks your pressure so high, the organisation of your team is so important. Are you going to chase him to the end or are you going to change your organisation and drop in a different way?
"It is difficult to change your mind because it is not just, click, change your mind. It is the timing of when to change your organisation and whether to continue playing the same way or to go to a zonal organisation."
On the physical demands under Bielsa…
"It is really, really, really tough. I think the Leeds players, for sure, understand what I am telling you. It is so tough because he is a very demanding coach.
"I can talk about my time when I was his player with Newell's Old Boys, with the Argentina national team, and with Espanyol. It was tough.
"I think from that period to today he has evolved. In many aspects, his teams are different. But I think the principles, the identity of his team, you can still recognise Marcelo Bielsa teams from the period when I was his player."
On whether Leeds can maintain intensity…
"I hope so because it is very enjoyable to watch Leeds.
"It is very difficult for me to be objective when it comes to Marcelo because with Jorge Griffa and Marcelo Bielsa, they are like my two footballing fathers and I am so grateful to them.
"But that is, I think, the big challenge for him to keep being consistent because it is a tough game to play and to develop the game that he wants to apply you need to not only be focused and concentrate but the physical demands are so high.
"I need to say that when he was in France, he called me and was asking me about England. I told him that he could be very successful here. I spoke very highly of the English culture, the English player and the identity here.
"I told him that he would fit in perfectly. It is exciting to watch him and see how he is going to keep up this physical level that is so demanding."
On Bielsa's teams being direct…
"I think Leeds are one of the teams that play out from their own box. They build from the back. But, of course, the way that Bielsa plays, he loves to be vertical. To go forward.
"You need to think in the moment that you recover the ball to go forward and to run. That is Marcelo's character. All or nothing. It is difficult to see Leeds draw games.
"He loves to be vertical, to play the first pass quickly. I think the middle of the pitch is just transition for him. He is interested in his own box and the opposition box. That is where you win or lose the games, of course."
On the detail behind Bielsa's preparations…
"When I was playing for the second team of Newell's Old Boys I remember we prepared in the week. There was not the internet back then. But he collected all the newspapers and in groups of three players, we went away with this information. We read the newspapers.
"If you read one journalist, maybe it is the wrong information, but if you read 10 newspapers, from Buenos Aires, from Rosario, from Cordoba, all over the country, then we could go inside the opponent and know every detail. We knew the formation, the players, who was taking the penalties, how many players go up for corners.
"[Compared to] this time, that information was basic. It is not only him who works in this way [now]. I think today all the coaches today are really well prepared. Today, we have the capacity to have all the information and it depends whether you want to use it. But at the time when he was my coach at Newell's Old Boys, he was maybe 20 years ahead of everybody."