BARCELONA -- Last November, Barcelona tweeted a photograph of Lionel Messi hugging Marc-Andre ter Stegen with the caption: "The two biggest reasons we are where we are right now."

The tweet drew outrage because fans felt it diminished the role of the other players in the squad and Barca followed up with another post explaining that "all our players contribute to our success." However, one year on, it remains undeniable that Messi and Ter Stegen are the keys to Ernesto Valverde's side prospering this season.

In a Barca side that is struggling in defence -- they have conceded more than nine other teams in the league and are winless in three ahead of Wednesday's Champions League game against Tottenham -- Ter Stegen's handwork, and footwork, has become increasingly important.

The Germany international brought up 150 games in a Barcelona shirt in the 1-1 draw against Athletic Bilbao at the weekend, but back in 2016 there was a real chance he would leave. It's no secret that summer the Catalans had a decision to make: Ter Stegen or Claudio Bravo. Luis Enrique's rotation policy wouldn't cut it anymore.

"You want to play, this is what it is about, this is what matters," Ter Stegen tells ESPN FC, unprompted, when asked to look back over his four-and-a-bit years at the club. "I don't think anybody would have been happy with the situation but I kept fighting and there came a situation when the club had to decide. It was not just my pressure, it was Claudio's pressure as well.

"The club had to decide one day. I think it was the right time for everybody. That the club decided for me was a sign, too, and this is why I stayed. It was a hard situation at that time, but I am happy that everything worked out well and that we're in this situation, celebrating 150 games."

New revelations in a book about Pep Guardiola, written by journalists Lu Martin and Pol Ballus, claim that Ter Stegen was actually closer to joining Manchester City than anyone realised, before Bravo eventually did. A passage in "Cuaderno de Manchester" says the player's wife had even begun the process to switch to Manchester University.

"This is the past already," Ter Stegen says when the book's claims are put to him. "What we need to do is look forward. But, of course, after the second season, there was a time when we had to decide and, of course, it's not just about me as a person, not as a football player. It's also about family, it's about my wife, and my wife is studying here in Barcelona.

"She's very happy and of course the first option for me was to stay here if all the circumstances would be fine and I would play. Of course, that would be the first choice. But when you're not happy, and at this time I wasn't really happy sometimes, you're searching for another way, for an exit maybe, for another idea.

"But, in the end, the option that I really wanted to have in my life was to stay here, to play for the club and be at the highest level possible. I'm really happy [with what] the club did and [with] how my wife managed the situation. It [wasn't] an easy situation. When you start to study here and then it's about to change a lot, or it might be (...) it's not really comfortable. It's not what I say as a footballer, [but] as a private person, a normal guy who wants the best for her, and I am very happy for her."

It casts a light on the life of a footballer which is not often seen beyond the transfer headlines. Behind every deal there is, on many occasions, a big personal decision to be made. A personal decision which involves wives, girlfriends, kids, family and friends.

Unlike the majority of his teammates, Ter Stegen lives in the city centre. If you spend enough time hanging around Passeig de Gracia or Rambla de Catalunya, you may even see him whizzing around on an electric scooter. It's hard to imagine him not keeping goal at Camp Nou, and it's become equally as hard for him to imagine living outside Barcelona, where he feels at home.

"It's good that people are happy seeing me on an electric scooter," he laughs when remembering last season's viral video of him. "I am really enjoying the time [living in the city centre]. I always try to get different perspectives, also getting to know the mentality.

"I think, since living here, I [have] improved a lot getting to know the people, how they are, what they expect. Every culture is different, so you need to adapt. I think, step-by-step, I am coming closer and I see that something's already changed. I am German, but now sometimes it's getting closer and closer to being a Catalan. It's funny how things are changing."

Ter Stegen has now played 150 games for Barcelona. Lucho Vidales

The 26-year-old has also developed on the pitch since he made his debut against APOEL in 2014 after signing from Borussia Monchengladbach.

"When I came I was 22 years old," he says. "There was big space for improvement and this is what we work every day on. My goalkeeper coach is very honest. He tries to make me even better. We find [things to work on], even if someone from outside doesn't see a small mistake, or even good things, too, I mean for me it's important to get good, honest feedback. That's what he's doing. That's how you improve. In the last few years I learned a lot.

"Every goalkeeper coach and every coach gives you new advice. You take what you think is best for you. My old coach at Monchengladbach, Lucien Favre, then when I came here with Luis Enrique, [Barca goalkeeping coach Jose Ramon] de la Fuente is still with me from the beginning, and now we have Valverde. Everyone gives you something very special. You get to know amazing people, which is most important, people who want the best for you. This is what I think is my happiness, I would say. That people are honest with me and try to make me better, not just on the pitch, but also off the field."

Since that night in Cyprus four years ago, Ter Stegen has been present as Barca have won one Champions League, three La Liga titles and four Copas del Rey. And it's collective success he is targeting in the future as he looks beyond his 150 games, not individual milestones.

"Winning titles with this team, with colleagues who you are with everyday, is what you want to reach, what you play for every day and what you are fighting for every season," he adds. "This is the objective. It always was and it always will be for the next years. We are all fighting for a perfect situation, to enjoy being together on the pitch and playing big football.

"There is always much more to achieve. As a footballer, you always want to get better personally. And if you get better personally, you make the team better. If I have the chance to be an important part for my colleagues, or someone they can look at and say he's doing good, he's motivated, this is an objective I want to reach.

"I want to be successful. That's what I want to be. Successful for me means being important for my team and hopefully for us to win a lot of trophies. That's not just my objective but the objective of everyone else."