The two stadiums are 366 miles apart. One holds more than 50,000 people, the other less than 10,000. The buzz as you walk up to the two grounds is a little different.

But nevertheless, one Barcelona fan appeared not to have realised that he was at the wrong ground and tried to get through the turnstiles at Exeter City’s modest stadium (St James Park), rather than Newcastle United’s hulking one (St James’ Park).

Staff at Exeter told on Thursday how they gently explained the mistake and gave him a seat for their third-tier match against Lincoln City rather than the Champions League clash he had hoped to watch.

“He looked absolutely devastated,” said Adam Spencer, supporter experience officer at Exeter City.

“I put him in a nice seat in the main stand. I thought, well, he’s closer to the pitch here than he would be in Newcastle, and we’ve got no VAR [top flight football’s video assistant referee system] so I thought he may have had a better night actually.”

But when Spencer went to check on him in the second half, the supporter had slipped away. News of the mistake has spread far and wide. A well-known opticians is trying to track the fan down to do some publicity about the error, as is a betting company.

“He must have seen it by now,” said Spencer, “But from my interaction with him on Tuesday, I would say he’s probably too embarrassed at the moment. I’m sure in years to come he’ll look back on his great night at Exeter City. But maybe not this week.”

Spencer said he was getting ready for the match when a member of the club’s ambassador team popped his head into the office.

“They said there’s a guy trying to get in a turnstile with a Newcastle v Barcelona ticket. I thought it was a wind-up. I got them to bring him round to the fan zone. He was probably in his late-20s, early-30s. Dishevelled look on his face. I could tell he had been through the wringer.

“He didn’t speak much English. He just told me: ‘Train, London.’ We think he had travelled down from London and just got off the train and walked straight up to the turnstile with his ticket and tried to use it. He told some of the supporters that his ticket cost £100.

“I told him: ‘Look buddy, I’m going to get you a ticket to come in here tonight. You’ve still got to watch some football.’

“I walked him up to the gate. I said, to be honest, mate, I’d rather watch Reece Cole [an Exeter midfielder] than Lamine Yamal [Barcelona superstar] anyway. But I don’t think he understood a word I said.”

By the second half he had gone. “Whether he was sat in another seat or had popped into the city to watch the Barcelona game on TV or drown his sorrows. I don’t know,” said Spencer.

“My guess would be he’s put St James Park in his phone. The railway station right next to the station here has the same name. And off he trots. That’s his planning done. He’s on a nice, relaxing journey. Until he gets here and walks up to the stadium and thinks, I thought the Gallowgate [Newcastle’s famous end] would be a bit louder than that.”

There has been scepticism about the story from some football fans and commentators.

Spencer said: “I guess it’s pretty unbelievable that you could make that mistake, but I think the biggest factor was that he didn’t speak much English. Spencer said he didn’t take a picture because the Barcelona fan was so abashed. “I didn’t feel right at the time to ask him.”

Exeter has never played Barcelona but one link is that they are both fan-owned.

Neil Le Milliere, a member of the supporters’ trust board that owns the majority shareholding in the club, said: “It’s typical of our club to sort out someone like that.”

Le Milliere said he was pretty sure the fan visited the supporters-run bar, The Famous Exeter City Real Ale and Cider Emporium, on Tuesday. “Lots of away supporters ask us why their clubs don’t have something like that.”

Some have wondered if an apostrophe led to the mistake. St James’ Park in Newcastle has one; Exeter’s is St James Park.

Veteran Exeter fan Clive Edmonds-Brown said: “The poor chap’s heart must have sunk. It’s a shame he didn’t bring the Barcelona team with him.”

Another supporter, Karen Blundell, said: “I am surprised he didn’t see all the home fans in red and white rather than the black and white of Newcastle United. Bit of a schoolboy error.”

But Spencer can sympathise. By coincidence, he visited Barcelona last weekend, booked for a tour of the club’s Nou Camp – and got lost on the way there. “I got on the wrong tube. I messed up but obviously not as much as him. I didn’t end up in northern Spain.”