How to replace a legend like Andres Iniesta? Sooner or later Barcelona will have to solve that conundrum, even if the evergreen midfielder continues to defy reports of his demise as he persists with star performances just a few months shy of his 34th birthday.
But while Iniesta continues to play a big part in Barca's latest treble bid, the Catalans are already looking to the future. And, in securing a purchase option worth just shy of €40 million on Gremio's wonderkid Arthur, those in charge at Camp Nou have taken a massive step in ensuring Iniesta's successor will be ready and waiting to take the king's mantle when he eventually hangs up his boots.
A native of Goiania, Arthur moved to Porto Alegre at the tender age of 14 to join the Tricolor's famed youth system. It was in 2017, however, that the diminutive midfielder would make the breakthrough. A brilliantly measured performance in his Libertadores debut against Guarani propelled him into the starting line-up and he has since made the spot his own, barely missing a game in the Brazilians' glorious run to Copa victory against Lanus in November.
His progression culminated in an other-worldly performance in the second leg of the final, where he picked up the man of the match award despite being forced off minutes into the second half. His big-game pedigree, then, is beyond doubt, and he has wasted no time in making a lot of fans in his native Brazil.
The youngster does not make the headlines for his goalscoring exploits or fancy tricks. Instead, in the vein of an Iniesta or Mesut Ozil, his great strength lies in an uncanny ability to spot the right pass and execute perfectly. At just 5'8" he is also a dead ringer physically for the Barcelona idol, and similarly capable of those startling bursts past defenders that Iniesta uses to such great effect to shrug off the attentions of markers.
Fellow hot talent Luan is one of the players who has benefitted from his team-mate's incredible rise to the first team; as has Lucas Barrios, the veteran Paraguay international still hitting the net on a regular basis for his club at 33. While the statistics say Arthur has contributed a solitary assist to Gremio's Libertadores campaign, that number hides his importance in getting his team moving in the middle, even if he is not charged with delivering the final killer pass.
Since coming under the wing of Gremio legend Renato Gaucho, a Libertadores winner as a player in 1983 and now in his third spell as coach, Arthur is also learning how to become a more decisive presence in the opposition area. "I'm a player who likes to have the ball at my feet, and organise play," he explained to reporters.
"As a defensive midfielder I see more of the ball, further back. But as a playmaker Renato is forcing me to get into the area, reach the goal and try to score, as well as thread the ball through. I am also forcing myself to support the attackers and wingers. I think that is where the difference has come, I am trying to get into the area more to feed those up front."
Such potential has not gone unnoticed. As well as Barca, who fought off interest from a host of other European giants to sign an option worth an initial €30m plus a further €9m in bonuses, Brazil coach Tite has also noted the talented midfielder, calling him up to the Selecao for September's World Cup qualifiers, although he did not see any playing time.
Barca's pursuit of Arthur, meanwhile, was constant and insistent. The youngster made a rare mistake - off-pitch, that is - by posing in a Blaugrana shirt accompanied by club director Robert Fernandez just hours after his masterful taming of Lanus, a gambit that did not impress those in charge at Gremio.
Whether it was that ill-advised publicity stunt or the blockbuster signing of Philippe Coutinho that pushed the signing onto the back-burner, Barca refrained from following up their interest in January. But contact between the two clubs was never lost and, at the start of March, a delegation from Porto Alegre arrived in the Catalan city to finally thrash out the details of the club's biggest transfer since Ronaldinho left for PSG in 2001.
It remains to be seen whether Barca take up their option in July, or whether Arthur will be allowed further time at Gremio to continue developing his game. The club's progression in the Libertadores will likely prove key in the decision, as will the fact that with just over 50 professional appearances the 21-year-old is still a relative novice at the highest level.
Arthur also has a point to prove to his own fans: that injury sustained in the final ruled him out of the Club World Cup as well as the first two months of 2018, and his introduction in Wednesday's state championship win over Sao Paulo was celebrated with ecstasy by the home support.
When it does come, then, the call from Barca to step into the shoes of someone like Iniesta presents a formidable challenge for the player. But Arthur has demonstrated so far he can live up to the hype, and those Iniesta comparisons will not faze him as he prepares for a move that could propel him into the world's elite.