The lights are out and everyone’s gone, even the kit man whose job it is to pack away and lock up. Well, almost everyone. Borja Iglesias is still at the Benito Villamarín, ice on his knee, bandage on his wrist, in his training kit. The teammate waiting to go to dinner has left – sorry, Andrés – and the entrance is locked but he’s inside talking about, well, everything really. The goal that brought Real Betis’s first trophy in 17 years and how it’s good getting kicked, pressure, popularity and being called the Panda, plus painting his nails and why more footballers should speak out.

There’s a lot to say. Fond of his Leica and rolls of 35mm film, when Iglesias finally heads towards an empty, silent dressing room where only his stuff remains, he pauses to ask the photographer whether they can go and take pictures together. “Just not this week; this week’s busy,” he says. “I’m going to Old Trafford.” And with that, he cracks up again.

Iglesias looks like a kid, a twinkle in his eye as if he still can’t quite believe he’s here, let alone there. “When the draw was made some of my teammates were like: ‘Ah no, [Manchester] United. It’s going to be tough,’” he says.

“And I thought: ‘Yeah, sure, it’s tough, but playing at Old Trafford? How cool is that?!’” Pretty cool, which is what most people think of him. Asked to sum him up, one player sends a voice note: “Borja Iglesias?” it says. “Outstanding footballer. Top man.” And that’s an opponent. Borja bloody loves football and football bloody loves Borja.

Of course they do at Betis where he scored in the Copa del Rey final, the fourth trophy in their history. But everyone seems to have a soft spot for the big, bearded Spain international. Feel the enthusiasm, the warmth and fun, and it’s easy to understand why. Talk to him for a little while – better still, talk to him for a long while – and it’s even easier. Nicknamed The Panda after a track by the US rapper Desiigner which his Celta youth team made their anthem, black and white bear tattooed by his ankle, this is the man who instead of complaining about his latest bruising from a centre-back, came off and immediately declared what fun he’d had with Real Madrid’s “noble” Éder Militão.

When he was a kid, Iglesias would wait at Santiago de Compostela airport in Galicia, autograph book in hand. At his parents’ home is a box full of stickers, signatures and snaps, a portrait of his passion. He recalls not daring to say a word to Ronaldo Nazário, countless pictures with Fernando Torres and how he admired Didier Drogba and Ruud van Nistelrooy.

“When we played PSV, I asked Ruud for a photo. I was so excited and my dad was a big fan. I talk to [Betis’s coach, Manuel] Pellegrini about him. And Manchester United represent my first memory of English football. [David] Beckham, [Eric] Cantona. They had a huge impact growing up. Going there is a gift.”

Although Iglesias has never been to Old Trafford, he has seen United live. In May 2017, he was at Balaídos, a B-team player at Celta when the first team faced United in the Europa League. That evening Marcus Rashford scored the United goal in a 1-0 win; six years on, Rashford is the only starter still at the club. He is also a man Iglesias describes as a “role model”, someone whose shirt he would like to add to a collection which is the perfect accompaniment to that box built up as a boy.

Iglesias has shirts from the biggest clubs: Madrid, Barcelona, Oviedo. He lists some of the names, recalls Torres saving one for him even though they never faced each other, and talks “tactics” too. There’s David Villa at New York City, Lionel Messi, Luka Modric, Karim Benzema. Joaquín when they were opponents. “Against Inter, I asked [Edin] Dzeko at a free kick,” he says, grinning. “Sometimes they do it first, which is nice. Some great player you admire and he asks you. It happened with Diego Costa. A friend of his was a fan. He says: ‘I have to have your shirt.’ I was like: ‘I’ll get yours, right?’”

Iglesias laughs. “On Thursday I’d like Rashford’s, of course. But I suppose he’ll be one of the most requested. The expert is Álex Moreno; he’s so fast. You go up to a player and he says: ‘Alex already asked in the warm-up.’

“Rashford was young when I saw him back then against Celta but he already had the ability to make the difference and he’s even better now: big but skilful, he can run beyond you, score goals, create, play in a variety of ways. Obviously, I admire him for the player he is, but also because of who he is: off the pitch he is an example, committed to social issues, bringing visibility, unafraid to express himself. It’s not a pose, and people see that.

“He has shown the power players can have, the responsibility to say: ‘Look, things are like this but we have an opportunity to leave things better.’ It’s important to be conscious of that. Sometimes it can be a headache, people don’t fancy it. But any problems it causes are minor compared with the positive impact. Others do act but more quietly, although that loses the visibility.

“Rashford does it in a very natural, organic way. And that’s how I feel about these things too.” Iglesias talks openly about mental health, the support he has had to seek at times, and has spoken out against racism and homophobia.

He talks of football’s responsibility to “create a safe space”, expresses his hope that new generations bring a “more open mentality”, and applauds Jakub Jankto’s decision to come out as gay, a step towards full normalisation. “In women’s football it’s totally normal,” Iglesias says. “They’re an example to us in that sense.” There is a pause. “And in many others,” he adds. As he talks, painted finger nails in many colours move, a message of inclusion and a reminder to himself.

“I first did that when the Black Lives Matter protests began,” he says. “I painted them black to make myself conscious. We have normalised certain comments that shouldn’t be normal; that was a way of having it present so that if things were said, I would think, act: ‘No, we have to correct this.’ Later I changed colours; the message applied against homophobia too. And now I like it.”

The first time the nails were spotted, criticism followed on social media but Iglesias managed it with clarity and calm, explaining why it mattered. Using those platforms, opening up and speaking out could have exposed him but it has brought affection – “maybe they don’t feel that nervousness to come and talk to you” – and brought him closer to people. So did the goals, a Spain call-up following.

So much for stick to football. “The more I find things to do outside football, the better I feel on the pitch. And that doesn’t have to be drawing attention to social issues necessarily; it can be finding creative things to do, other interests. It’s as if one thing fosters the other. When I limit myself to football, I feel worse: as if focusing solely on football creates pressure, a feeling of being overwhelmed. Getting out of that helps.

“It’s normal that some don’t step outside football because we can feel vulnerable, vertigo. But we needn’t be afraid: we’re not born with every lesson learned. If you like something, go find out about it. Listen to people who know, because one of the luxuries of football is the chance to meet so many people.

“Our profession is our passion, the world we’re in, and often the life of a footballer is closed in on itself. Sometimes you also have to look beyond to realise: ‘Bloody hell, how lucky are we?’ I feel a lot of love, for example.

“I got my debut at 20 but didn’t play again in primera until I was 25 and I think that does make me value it more. In my third year at Celta B in Segunda B, I thought: ‘Maybe this is what football has for me.’ Just enjoy it, don’t think too much. But then my last year was amazing, changing everything. I get into primera and think: wow. Not getting there so fast helps you. It wasn’t that long ago that I was playing up to my ankles in mud. Everything from there is a luxury.”

Even getting kicked. “I like the battle,” Iglesias says, laughing. “I need to feel that contact, live that duel. Until I was 15, 16, I was more scared but I’ve grown. I like them on top of me, bumping into me, hitting me. I like to feel: here he is.” He says he dislikes defenders leaving him alone, leading to discussion about the importance on-field reference points, the kind of player he is – one who could play in England – and how he evolved to suit everyone. The analysis continues with him lauding Casemiro’s underappreciated capacity to “take a touch and project the team every time he robs the ball”. He thinks, that’s for sure.

“Well, I try,” he laughs.

Sometimes, though, it’s best not to. “You know, occasionally I’ve thought: ‘I wish I didn’t care,’” he admits, and he’s not alone: the other day a teammate was reading The Art of Not Giving a Fuck on the bus. “Since I was a kid I would go over and over things and that’s created problems for me: feeling sick or anxious. Sometimes I would like just to say: forget it. And I do sometimes tell myself: just go and do something else, purely for enjoyment. Let go.”

On the pitch too. “This year I’ve had two very similar examples: the typical run through from halfway. One, I scored; the other, I nearly tripped over the ball. And the difference was precisely that: thinking. In the first, against Girona, it was all about execution. In the second, against Atlético, I’m completely alone running towards [Jan] Oblak, thinking: ‘What should I do?’ And there’s a moment when I basically leave the ball behind, like I’ve forgotten it. I’m at my best when everything flows.

“I usually take a moment before the warm-up when I do some meditation – as much as you can because you’re in a busy dressing room with music on and everyone immersed in their own ritual. I give myself a couple of minutes to breathe calmly and think. ‘Bloody hell, I’m going to get the chance to play another match.’ That helps because go back five years, and I would be desperate to be here.”

Alone at the Benito Villamarín but about to head to Old Trafford. And that, the Panda says, is pretty cool.