Lionel Messi knew little about Arthur when the midfielder arrived at Camp Nou.
The Brazilian joked in the summer of 2018 that an added bonus of joining Barcelona would be the chance to check if Messi "is from this planet or not".
Like many of us, Arthur had often wondered if the six-time Ballon d'Or winner was really human.
Messi, though, was not as familiar with Arthur's talents. He was, therefore, pleasantly surprised to discover that the new arrival's style of play bore a striking resemblance to that of a former team-mate.
“I didn't know that much about Arthur but he seems similar to Xavi," the Argentine told Radio Catalunya. "He’s very safe and trustworthy. He has La Masia style: playing short passes, without losing the ball. He grasped it very quickly, the dynamic of the team.”
Those Xavi comparisons just kept coming during Arthur's impressive debut season at Camp Nou. Indeed, perhaps the biggest compliment one could pay him is that Barcelona always looked like a better team with him in the starting line-up.
He was ridiculously comfortable in possession of the ball, and moved it quickly and effectively.
Even Xavi was impressed.
“I see myself in Arthur,” the Barca icon told Radio Catalunya. “He thinks quickly and he still has work to do, because I improved my game at Barca and I would not have got so good in another school.
“But Arthur looks mature. The priority in the middle of the pitch is to not lose the ball and he makes it look easy. He plays well and steadily. I see great potential in him.”
He is not going to get the chance to realise it at Barcelona, though.
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On Monday it was confirmed that Barca have reached an agreement to sell Arthur to Juventus in a deal worth an initial €72 million ((£66m/$81m).
He clearly does not want to go. And the fans do not want him to leave – certainly not as part of what is effectively a swap deal involving Miralem Pjanic.
Arthur is not having a good season. Even before he was, according to coach Quique Setien, distracted by the transfer talk, the 23-year-old was performing poorly.
Setien's appointment in January should have been a positive development for Arthur, given the former Betis' boss possession-orientated style of play.
However, Arthur has arguably regressed. He has grown increasingly inconsistent, and looked slow and ponderous on the ball.
Indeed, it was no coincidence that Setien's decision to replace him with Riqui Puig in last Tuesday's crucial win over Athletic Club changed the entire complexion of the match.
The youngster brought the energy and incision that had previously characterised Arthur's game.
So, the issue is not so much that Barca are selling Arthur – but that they are replacing him with Pjanic.
If Arthur has been poor this season, Pjanic has been worse.
The Bosnian has failed dismally to adapt to Maurizio Sarri's brand of football at Juventus and has, rightly, been deemed surplus to requirements.
Quite what Barca are going to do with him is anyone's guess, given Sergio Busquets, Frenkie de Jong and the aforementioned Puig all look better options in the middle of the pitch.
Pjanic was a fine footballer but he is 30 now and evidently in decline. The last thing this Barca squad needs is another ageing player who is clearly past his best.
It is a signing that makes no sense from a sporting perspective but then, this is not really about football – it's about business.
Barcelona right now are more concerned with balancing the books than constructing a Champions League-winning squad.
That is hardly surprising, of course.
They may have topped this year's Deloitte Football Money League but they have spent close to €1 billion over the past six years and arguably only made five good signings: Luis Suarez, Marc-Andre ter Stegen, Samuel Umtiti, De Jong and Arthur.
However, Barca are not just wasting money – they are also wasting Messi's final years at the very highest level.
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The Argentine turned 33 last Wednesday and he remains an outstanding player. The problem is that Barcelona have never been so reliant upon his genius.
The Blaugrana have scored 72 goals in La Liga this season; Messi has been directly involved in more than half of them (21 goals, 17 assists).
He has always posted ridiculous numbers in that sense, of course. What is significant now, though, is just how involved Messi is in Barca's play.
He's had 2292 touches in La Liga this season, which is more than he racked up during the entire 2008-09 campaign (2158) – and nearly as many Barca's midfield lynchpin Sergio Busquets this term (2457).
Messi's also completed 151 dribbles – nobody else has managed more than 43 (De Jong).
Essentially, the captain is having to do everything. He has to drop deep to make things happen in midfield and then get forward to set up or finish chances.
It is a ridiculous situation for a club of Barcelona's size and revenue. But no longer surprising.
After all, Barca have required a Luis Suarez replacement for two years yet somehow found themselves in a position where they had to make an emergency signing in February of Martin Braithwaite just so they had enough numbers in attack for the remainder of the campaign.
The subsequent suspension of play caused by the coronavirus outbreak only further highlighted the deep divisions at Camp Nou and the scale of the club's financial problems.
In truth, though, one need only watch them play to understand how badly the club is run, with their star player now surrounded by a largely sub-standard supporting cast.
Barca may like to label themselves 'more than a club' but right now they're less than Messi deserves.