“Since I first stepped into professional football, I had the target to be a professional manager.”

There are many different routes to the top job. Some are longer and more complex than others; some take decades, some take months; some are fast-tracked straight out of stellar playing careers. But you won’t find many like Rubén Sellés.

It’s amazing to think the Spaniard does not turn 40 until the summer, such is his wealth of experience – not just in work, but in life. Sellés has crammed a lot into his first four decades. Most of it in the name of football.

It’s no surprise, with so much to fit in, that Sellés started early. He was only two years old when the 1986 World Cup got under way in Mexico, in which Spain showed gradual improvement – losing to Brazil, scraping past Northern Ireland and slicing through Algeria.

That set up a second-round meeting with Denmark – an exciting team who had dismantled Uruguay 6-1 in the group stage and overcome West Germany, the 1982 runners-up, 2-0.

Cue a performance for the ages from Spain, then one of international football’s great underachievers, who came from a goal down to win 5-1 thanks to four goals from Emilio Butragueño.

In true Spanish style of the time, they were eliminated in the next round by unfancied Belgium in a penalty shoot-out, but Sellés, who had just turned three, was already hooked.

“I remember asking my father for the Spanish shirt of Butragueño,” he smiles. “I remember asking for that and he was not a big fan because Butragueño was the Real Madrid striker and we are Valencia fans! He was not happy with that connection.

“I just remember that red shirt and Butragueño… I wanted to dress like that.”

With reluctance, his father bought the shirt. “I don’t know if I still have that shirt or not, but he did it,” he grins. Pleading for Butragueño’s Real Madrid No 7 jersey may have had a different outcome, but the Spain compromise was deemed just about acceptable.

The Sellés family are not just Valencia followers from a distance, but regular match-going fans whose passion for the club has passed down through generations.

For Rubén, he would attend games at Mestalla with his grandfather in the club’s golden era.

won the Spanish Cup in 1999, the league in 2002 and 2004, and the UEFA Cup in 2004.

In that same period, at the turn of the century, Valencia reached back-to-back Champions League finals. They lost them both – to Real Madrid and Bayern Munich, the latter on penalties.

“End of the world? Absolutely,” Sellés shakes his head, still haunted by the decisive spot-kick in 2001, missed by one of his predecessors in the Saints hot seat, Mauricio Pellegrino.

“When you are a fan and you have these experiences, for Valencia and for the club it was the time to get it, because it looked like now or never. Unfortunately, it has been never, but that night it was that close that we almost got it.”

By now Sellés was in his late teens and already embarking on his own coaching journey.

He played, too, but is modest about his abilities. “If I was a good player, I would make it,” he shrugs, labelling himself “a right-back or a centre-back, really strong in the defensive moment but not with the best aptitude in possession.” Determined? “Exactly, that’s a good way to describe it,” he laughs.

If he wasn’t going to play the game professionally, Sellés was going to do his damnedest to make sure he was involved in another capacity instead.

At 16, he was already managing the Under-9s of the club he played for in Valencia, Parreta CF, before starting his studies in physical science.

“When I needed to go to the university, my idea was to be linked by sport,” he explains. “I started at the university that specialised in football, and then everything came a little bit around it.

“I finished my bachelor (degree) and I still needed to continue growing up, so I went to Barcelona to make an MBA (Master of Business Administration) with the people in Football Club Barcelona.”

Sellés namechecks Paco Seirul·lo, who he refers to as Barcelona’s “meteorologist” as a key figure, a man described by Pep Guardiola as “the best physical trainer I have ever worked with”.

Seirul·lo’s impact on Barcelona dates back to 1978, when he was mostly devoted to coaching the club’s handball team, dominating Spanish and European competitions.

It was Johan Cruyff, interested in learning from other sports, who promoted him to physical trainer of the club’s football team in 1994, believing in outside perspectives.

At a time when fitness in footballers was built on gruelling pre-seasons and hill runs, Seirul·lo’s approach was different. “Like that we lose time and energy,” he reasoned. Instead, he incorporated agility and conditioning exercises into sessions with the ball, so all forms of training were integrated and technical aspects not neglected. Naturally, the players preferred it, and the team kept winning.

Sellés eventually graduated with a PhD, also coaching the university football team, and started his UEFA B Licence.

“I had some mates from the university who were linked with professional football,” he says. “One day, because I had all this background and I was having conversations and everything, the call just arrived: ‘we have this opportunity, we need somebody like you to be on the technical staff.’

“It was not a massive position, but it was the position that opened for me in professional football, and I took it.”

That should come as no surprise. If there’s one constant through Sellés’s unpredictable life, which has now seen him coach professionally in seven different countries, it’s his tendency to say yes to new opportunities. He loves to test himself; he loves to learn.

“I don’t know what a comfort zone is, to be honest with you. I’ve been living out of that comfort zone for 15 years,” he states. Fundamentally, it’s this approach that has taken him so far – in every sense – so quickly.

From working as a fitness coach at Greek club Aris Thessaloniki, aged 25, he performed a similar role for Villarreal’s youth team in Spain, before travelling to Russia to be an assistant manager.

He later worked as an assistant for Aris, and in Azerbaijan and Denmark; as a data analyst in Norway; and even returned home to manage Valencia’s Under-18s before joining Saints from Copenhagen, Denmark, where he had gained more experience as a first-team number two.

Those moves spanned from 2008 to 2022, a 14-year period in which Sellés gained a uniquely broad knowledge of how football clubs operate.

He understands the role of the manager, the assistant, the fitness coach, the physio, the sports scientist, the analysts; he understands languages, cultures, personalities. All because he grabbed every opportunity that came his way.

“I think it says about me that I can do almost everything that I want to do, I am ready to invest what I think is the proper thing to invest,” he says. “Sometimes we need to be separated for a long time with the family, but as a family we decide to do it.

“I think it just put me in a position where I can understand almost every single point of view, but it is also making my life easier – I have 17 nationalities in the dressing room with different backgrounds, different religions, but because of my past I have touched almost everything in one country or another country, so I know exactly how they feel and exactly what they need. I think it is a big advantage.

“I think it just says that I was a person that didn’t wait for the opportunity – just go and try to get it, and try to be as honest and direct as possible, and adapt himself to a different scenario, which I think is a very, very important quality in life.

“Now when we are here talking, when I have a fantastic technical staff in Southampton, I know what is required to make every single activity they make, so I can demand exactly what I can demand from them, and I know how to not overload them. That is a big advantage for me.

“I know how much it takes you to analyse a football match and it is not something you can make from one hour to the other. I know how much it takes for you to prepare a training session, or a video session, or to analyse the game from a statistical point of view – I did almost every single job in football, so I understand and I can demand.”

Sellés has faced challenges aplenty. Azerbaijan and Russia, he admits, were particularly testing ventures.

Even coming to England, less of a culture shock and a language he could already speak, was difficult, he says, because it took a while to find a house he could move into.

“It is not really important, but you have the feeling that everything is temporary, and sometimes that is not the best feeling,” he plays the situation down, but it’s a huge amount of upheaval and emotional strain.

So why do it? Why put himself through this continuous back and forth across Europe, from country to country, job to job, each role asking for something different to the last?

His motivation, right from the start, was to get to where he is today. Coming from a university background may have accelerated his education and enhanced his contacts, but how many top jobs go to people who haven’t played the game professionally?

“I always wanted to be close to football, but I thought it was very difficult to arrive – very, very, very, very, very difficult to be a manager,” he stresses.

“But as soon as I stepped into professional football and I watch what is required, I always wanted to try.

“I always wanted to be there, to make one step forward and move from one position to the other, from one league to the other, until the very top.”

As has been on trend throughout his unusual career, things have moved at a pace for Sellés even since arriving in Southampton last summer as first team lead coach.

Having joined a club that was settled under a long-term manager, the Spaniard has already worked under two bosses and taken the job himself before the end of his first season in England.

It’s always an intriguing transition, from assistant to manager, and one that often comes with scepticism.

The impression is that the number two is usually the “good cop” and liked by the players, which was evident after Sellés masterminded a 1-0 victory at Chelsea in his first game in charge, prompting hugs aplenty as the players encouraged him to bask in the applause of the travelling Saints fans at full time, playfully shoving him towards the away end.

But how does he maintain that relationship in a squad of 30 first-team players when only 11 can play?

“I didn’t have to change the way I am with the players,” he says, sternly. “That’s the big thing. You are the person you are – it doesn’t matter which role you occupy. You need to be the same person.

“Yes, my responsibilities are different right now, but I didn’t think I need any kind of approach with the players – I just need to communicate and make decisions that before I didn’t need to make, but I do it in the same way.

“If somebody feels that it is a little bit different, or there is more distance, then it’s not on me, because I just feel that I am doing exactly the same. But of course when you need to make decisions, it can put some distance with some people.”

Sellés is naturally likeable, but not desperate to be liked. There has to be a degree of coldness to be decisive enough to start a new life as often he has, but his people skills are a major strength; another learning from his past is how to forge new relationships quickly.

When Kyle Walker-Peters describes his new boss, he breaks it down to his ability to use the right words at the right time. “Rubén’s gone about it in the way of working on people’s mentality as opposed to pointing out what they’ve done wrong,” the defender observes. “Everyone knows when they’ve made a mistake, but when you do make mistakes, you have to continue playing.”

Buzzwords like “we” and “trust” are more common in the dressing room. Letters have been written to staff members and even partners, thanking them for their support, acknowledging their sacrifices and encouraging one more big push to keep Southampton in the Premier League.

Publicly, Sellés refers to “the house”, meaning the club as a whole – the culture and relationships within the training ground between players and staff. It’s “the house” because the people living inside must be a family.

“We have standards, cultural standards, that we need to respect, and that’s what we are working on now – to put it back in the house, in our behaviours, in the way we do things, and then the new players, or the foreign players, need to understand what does it mean,” he explains.

“If they want to be successful here, they need to find their way into those cultural aspects from us. Of course, in that culture there is open house for everybody, but the principles are always there, and we should not forget.

“I think it’s simple because some of the time there is a grey area with a person coming from one background who understands something different, and I can guide them into the way that leads into a better understanding from one to each other. Does it make sense?” he asks, leaning forward in his seat intently.

“At the end of the day it is one of the principles of leadership. You will always have different characters – it doesn’t matter if you live in a football club or a big company. You will have different characters and you need to analyse how you get the best of them.

“Our target at the end of the day is to elevate everybody to the next level – it doesn’t matter in which position in the house or which position in the squad they have. When they finish with us, they are a better player, a better person than they were before.

“For that, you need to know them, you need to analyse them and you need to see how they react in different environments. That is not always easy, but this is what we want to do.”

It’s clear he wants to challenge his players. A fortnight ago, Sellés publicly demanded more from Roméo Lavia, one of Saints’ most impressive performers this season. “I don’t improvise,” he smiles. Everything is planned out, with a method behind it. Lavia excelled in the games that followed, completing back-to-back 90 minutes for the first time since August and earning a first call-up to the Belgium senior squad.

When Saints were beaten at home by League Two opponents Grimsby in the FA Cup, many managers would insist on getting the result out of their system immediately, grateful for another game to put things right three days later. Sellés did the opposite.

“I said it’s very important when you have a defeat like that you sit and you reflect. It’s not like you move forward and try to forget – we are not forgetting. We cannot forget because if we forget, we will make the same mistakes,” he declared, before overseeing four points from the next two games against Leicester and Manchester United, with two clean sheets.

“I was very pleased with the reaction,” he nods. “I think they did an amazing job – all of them. All of the boys, all of the technical staff, they are working really good and the result reflects of what we are doing and what the individuals are putting in for the club.

“I would be very pleased to keep this team in the Premier League. I think we need to go one step at a time, be careful with the message, but I will say that yes we can do it, and we will do our best to do it.”

It’s sure to be a rocky road for the next couple of months – not just for Southampton, but for all nine clubs entangled in this season’s unprecedented survival scrap. Luckily for Saints, they have a manager who’s never more at home than when he’s outside his comfort zone.

Whatever that is.