There is a pause from the 20-year-old, a stern root around in his memory. Still, he is unable to offer a starting point to his journey to Chelsea goalkeeper.

'I began playing football quite young, the summer before I turned five, and at some point I was just in goal,' Bergstrom says matter-of-factly. 'I was tall, so I think that meant I was always the goalkeeper.'

As we sit in the luxurious Four Seasons Hotel in Philadelphia – one of the few buildings with doors big enough for the 6ft 7ins Finn – it's safe to say Bergstrom was put on the right path all those years ago.

He has already represented his country at senior level, and been involved in Champions League match-day squads with Chelsea. Bergstrom also embarked on his first loan spell last season as he spent time with Peterborough in League One.

All are impressive building blocks and why Bergstrom wasn't overawed when called upon this summer to feature for Chelsea during our pre-season tour of the United States.

The goalkeeper played against Wrexham – he produced an excellent stop to deny Ollie Palmer – and also was used off the substitutes' bench in our final Premier League Summer Series fixture against Fulham.

But back to Bergstrom's journey to Chelsea. How did a young goalkeeper born in the Finnish archipelago Pargas find his way to west London?

'Chelsea scouted me for the first time when I was 13,’ recalls Bergstrom. ‘They followed my progress from that point. A lot of things happened – I had trials at different clubs – but Chelsea always kept that interest.

'I played a couple of national team games at around 15 years old and I had other teams in England interested, but my heart was always for Chelsea because they were first.

'I knew a lot of people, and some players, so when the time came to make a decision it was an easy decision to sign the contract. It was a long process but I am very happy with the choice I made.’

It sounds somewhat simple. Bergstrom explains that it wasn't the case, especially as there came a point in his youth that goalkeeping had lost its allure.

'When I was around 10 or 11 years old, I wasn’t really enjoying it as much,' Bergstrom says. 'So there was a period when I was playing for my local team out on pitch and for my club at the time, TPS, in goal.

'So I played both and I did love playing on the pitch – you get to score goals! But when I reached 14 though, I was only playing for TPS. From that point, I was always in goal.

‘But playing out on the pitch was important; it allowed me to develop with my feet but also understand the game from a different perspective and different positions on the pitch. It helped a lot.’

Bergstrom arrived at Cobham in 2018 and assimilated into life in England. There was progression through the Under-18s to the Development Squad – and also sessions undertaken with the men's first-team squad.

Last summer Bergstrom took the opportunity to test himself at first-team level with Peterborough. The Football League can be an unforgiving environment for a young goalkeeper, but he made 28 appearances in all competitions for the club.

He says: ‘I really enjoyed it. Playing Tuesday-Saturday every week, the focus was always on the games. Training almost became secondary, so it was a very different approach.

'I didn’t feel it was a huge shock; people say that first loan into men’s football can be. Maybe it was because I came from Finland and the facilities were more similar.

'The biggest thing was to learn to play for the points. Nothing else mattered. Win at all costs.'

It was during Bergstrom's loan spell that Peterborough were drawn against Chelsea in the EFL Trophy. The goalkeeper started for the League One side in what proved to be a 4-2 win for our Development Squad.

'To be honest, that game was a very interesting experience,' he says. 'To play against a team that I basically knew everything about was strange. Yet it was a good opportunity as it is something that could happen in the future in my career.

'In the build-up, I knew everything exactly. I knew the players, apart from maybe one or two, I knew the tactics. I knew what the coaches are like. It was interesting for sure.’

That game was memorable for the goal scored by Cesare Casadei; the Italian found the top corner from 35 yards. Bergstrom had no chance.

‘We don’t need to talk about that,’ Bergstrom says with a laugh. ‘But Cesare has mentioned it during the tour, yes!'

Toward the end of Bergstrom's time at London Road, he received a maiden call-up to the Finland senior side. It was a youthful squad that took on Sweden but an experience that Bergstrom, no matter what comes next, cherishes.

'It was nice to play the game and I have that ticked off,' he says. 'I’ve played for the national team now and there are only a certain number of people to have done that. It was a honour.

‘It was good to meet the senior staff and if I go there again in the future, it will be an easier transition. There was a lot of family there and players I knew, so it didn't feel like it was a massive step for me.'