However, there are certain players who have benefitted from his arrival the most.
Biggest improvements
Ousmane Dembele
Xavi's words about the Frenchman's potential to be a better player than Kylian Mbappe seemed surreal at first.
Surprisingly, they now make sense as the 24-year-old has grown into a different kind of player who is finally serious and committed.
Dembele has got all of his 11 league assists this season exactly under Xavi – he is leading the way in La Liga in this stat.
Gerard Pique
The Barca veteran was considered too old for being first-team material in the first half of the season. Pique was easily losing his opponents and conceding unnecessary fouls.
Now he's a player Blaugrana are having tough times without. Both tactically and physically, the 35-year-old reminds us of who he was in his prime.
Eric Garcia
The 21-year-old is now definitely good enough to start difficult games – his outings against Levante and Eintracht Frankfurt (the first leg) prove it perfectly.
While still being a quality passer, Garcia has also improved in the defensive aspect, winning lots of duels and recording plenty of crucial tackles.
Luuk de Jong
The Dutchman was expected to be Ronald Koeman's dark horse, but he only scored one goal with his compatriot in charge.
The 31-year-old went on to become a real difference maker under Xavi. He is finally dangerous aerially and is a real goalscoring threat in the last minutes of the game.
De Jong has netted 6 goals since January – and 5 of them came at a moment when we badly needed it.
Marc-Andre ter Stegen
The goalkeeper was heavily criticised by many early in the season, but he's starting to find his groove.
On several occasions already, Ter Stegen's crucial saves have won us league points. His ball distribution skills have seemingly become better as well.
Sergino Dest
The American was one step from leaving Barcelona in January but he has proven he could actually be a regular starter under Xavi.
Dest used to be blamed for his poor defensive contribution and inability to win ground duels.
The wing-back has definitely improved in this respect and was praised by Xavi at least twice this year.
Biggest downgrades
Memphis Depay
The Dutchman used to be Barcelona's top goalscorer under Ronald Koeman. He wasn't in his best form with Koeman in charge, yet he certainly had a few great games in which he made the difference.
His decent form is no longer there as he's clearly losing competition to Pierre-Emerick Aubameyang, Ferran Torres and maybe even Luuk de Jong upfront.
Nico
The 20-year-old was sometimes starting games under Koeman – this was the period when he established himself as a potential regular starter.
The player has turned into an impact sub for Xavi and only enters the pitch to add some needed freshness to the midfield.
