Eight months later, Cesc Fábregas returns to England a changed man. The stage will be familiar, his face too, but the Barcelona midfielder insists the footballer is not. He has evolved since returning home. Less decisive perhaps, less dynamic too, but better.

Superficial judgments point at a dip in form; Fábregas points at something quite different – a change of country and a change of concept. On Tuesday night the man who supposedly had the advantage of not needing to learn anything insisted that he had learnt a new game. He is no longer a player who at Arsenal was, to use his own words, "not very good at all tactically".

They are fond of the phrase Barcelona DNA in Catalonia. Barça players, the theory goes, are somehow born differently. La Masia, the stone farmhouse that was the actual and spiritual home of young footballers for decades, does not just produce good players. It produces a specific type of good player. Technical, intelligent players, not just footballers who use a system but footballers who understand how to use it.

That is especially true of the central midfielders. As one Spanish commentator puts it: "Show me 20 kids in a park and I can tell you which ones play for Barcelona." A line of historical continuum can be drawn from Pep Guardiola through Ivan de la Pena, to Xavi, Andrés Iniesta, Cesc and now Thiago.

At 24, exactly midway between Iniesta and Thiago, Fábregas was the link they needed to ensure continuity. Importantly, they said, he was Barcelona already. He had played with Gerard Piqué and Lionel Messi as a 13‑year‑old. Unlike Javier Mascherano, he did not need to be "reprogrammed". Arsenal had been a finishing school, the perfect way of rounding off his education. Guardiola had made a point of thanking "Mr Wenger" for making him the player he is. He had been in London eight long years; "half my career", as he put it. But, ultimately, his game was their game.

The first few months at Barcelona suggested that the analyses were correct, but there was a shift in his education required – a shift in style, too. In his first 23 games Fábregas scored 14 goals, more than any other midfielder in Spain. He was given a free role as a false No9, like Messi. The pair appeared to understand each other perfectly. But then as he retreated further into midfield, the goals dried up. He has scored just one in the last 19.

If that sounds like a regression, it should not. Barcelona had given Fábregas freedom to play while he learnt how to adopt a more rigid, tactical role. His productivity may have diminished but Barcelona's has not. According to the former Arsenal midfielder he did need a re‑education after all.

London may not see London's Cesc Fábregas on Wednesday. They may not appreciate as much, either, but he thinks they will see a better one. Guardiola has adapted him. He admits that there is greater responsibility now; his movements are more in sync with those of his team-mates. You could almost call it rigid. He would prefer to call it more intelligent. His team are better for it.

"I feel I know more what my position now than I was at Arsenal – at Arsenal I was tactically not very good at all," he said. "I did whatever I wanted. Now I have to think more about the team tactically. Before I was going up and down and sometimes a little bit lost in the important moment because I wanted to do everything. Now, my team-mates are more experienced than me and I trust them – they have told me to be calm, to stay in my position."

If he has changed, Chelsea have not. Or more to the point, they have, but they have changed back again. Fábregas recalls Arsenal games against Chelsea always following the same script: "We would dominate the ball, keep possession, create chances and then," he says, pausing for effect, "… a counter-attack, [Didier] Drogba, goal! They have a super-fast counter-attack and it was a film that we saw again and again.

"With [André] Villas Boas they tried to have the ball a lot more, they tried to not play so many balls long and to not seek out the second ball quite so much. Now they have returned that Chelsea that made them great and led them to win the Premier League and reach Champions League semi-finals and finals. Drogba brings the ball down well, he is very quick, he is strong. They are a very dangerous team for us. They are like motorbikes now when they break forward.

"I follow the Premier League every weekend and I have seen a lot of Chelsea this year. They have changed radically. They are playing incredibly well, I think this is their best moment of the season. With Villas-Boas they tried to be different but they are now the same Chelsea as I knew when they left." He is not the same Fábregas they knew when he left.