As Christian Pulisic contemplated the possibility of a dream £58m move from Borussia Dortmund to Chelsea in January, he turned to one of Arsenal’s best players for guidance.

The 20-year-old’s mind was pretty much made up once Chelsea made their intentions clear. But swapping the reasonably sized city of Dortmund for the vast English capital can be a daunting move for anyone, let alone leaving the Bundesliga for the Premier League.

But who better to ask all about it than Pierre-Emerick Aubameyang - a man who made the same decision 12 months earlier and gone on to be a huge success.

There were obvious differences between the two transfers. For starters, Arsenal secured Aubameyang’s signature rather than Chelsea and the forward joined straight away, whereas Pulisic spent the second half of this season back on loan at Dortmund.

However, the crux of the decision and the many challenges that awaited was pretty much the same so Pulisic picked up the phone.

“When the possibility of my transfer to Chelsea came around, I reached out to him,” Pulisic told Standard Sport. “Even though Pierre-Emerick left Dortmund for Arsenal, we remained in contact. I have spoken with him on and off ever since he moved here.

“I asked him how it was in London and stuff. He loves it here. He is a big city kind of guy, you can see that and he has told me about a few places to go see.”

It is not the first time in his career that Pulisic has turned to Aubameyang for counsel. There may be 10 years between them, but they quickly formed a close friendship at Dortmund.

Pulisic joined Borussia Dortmund’s academy at the age of just 15, as Aubameyang was in his first season at the Bundesliga club.

Such was the USA international’s quality, they were soon playing together on the pitch. The attacking midfielder made his professional debut as a substitute in January 2016 against Ingolstadt, where Aubameyang naturally got both of the goals.

Their love of basketball, as well as football, ensured they formed a close bond, one that has had a huge and beneficial influence on the younger man’s career.

Pulisic added: “It was a very good friendship when we played for Dortmund together for a few years. He was there when I first broke into the first team and we had a nice link up on the field.

“He taught me a lot. That was one of the coolest things about him. He’s a very humble guy and perhaps people don’t know that about him.

“He was a lot older than me but took me under his wing. Not all older players are as welcoming or as accepting when a young guy comes in.

“But he was always very kind and wanted to be there if I had anything to ask. He went out of his way to help me. I will always be thankful for that.”

That is clearly not going to change, even though they now find themselves playing for two fierce London rivals.

Aubameyang, who has scored 41 times in just 64 appearances for Arsenal, will be a major threat to Chelsea’s hopes of winning the Europa League Final next week, a game that Pulisic won’t be able to participate in.

“We have bantered about that already,” he revealed. “I have told him ‘you can score one goal in the Europa League Final, but you can’t win. That’s it!’

“I knew that he’d do well in this country. He did it in the Bundesliga. He is just a guy that will always score goals. He will work hard and find that right spot. He is what a great striker can do.

“Does seeing how well he has done in the Premier League give me the confidence I can do the same? Yes, absolutely.

“It’s going to be great for me because I will always have a guy like him to take advice from and to learn from.

“It’s great to still have that relationship even though we are not going to be friends when we play against each other.”

It is not the only challenge Pulisic has to face. With Eden Hazard expected to leave Stamford Bridge for Real Madrid and Chelsea facing a transfer ban, he will be under pressure to perform.

Manchester City’s second successive title win, having accrued 198 points in two seasons, makes bridging the gap a very tough prospect for Chelsea.

But Pulisic concluded: “I won’t be intimidated. At Dortmund we had experience of competing with Bayern Munich the whole time.

“Obviously Bayern have a very strong team, but we were so close to winning the championship this year.

“At Chelsea, we are going to go into the next season with confidence, we want to go in right away from the start and compete to the best of our ability. That’s what we are going to try to do.”