Indeed, while the Argentine's excellence was able to paper over the cracks, it was Neymar's departure in 2017 that really sent shockwaves around the Camp Nou. Given that came towards the end of the Xavi and Andres Iniesta era, the Catalan giants were losing so much.
In turn, Neymar's move led to a huge spending spree that saw Ousmane Dembele and Philippe Coutinho arrive, along with Antione Griezmann in the summer of 2019. Despite the huge expenditure, none of them worked out.
Spanish publication Marca recently highlighted the decline.
Barcelona's squad 2007-08
The final days of the Frank Rijkaard era saw Messi, Xavi and Iniesta start to emerge as a force, although Thierry Henry, Samuel Eto'o and Yaya Toure were still major parts of the set-up at the time.
Barcelona's squad 2008-09
The historic appointment of Pep Guardiola led to the removal of Ronaldinho and Deco as big parts of the Barcelona squad, while Gerard Pique had replaced Gabriel Milito as Carlos Puyol's central defensive partner.
The signing of Dani Alves that summer would go down in history as Guardiola won the treble.
Barcelona's squad 2009-10
Zlatan Ibrahimovic was swapped for Eto'o in an effort to give this side another point of attack. Still, the move worked out badly as the former did not see eye-to-eye with Guardiola and the latter was winning his second treble on the spin under Jose Mourinho at Inter Milan.
Pedro, however, was just the latest of the club's academy graduates to hit the big time.
Barcelona's squad 2010-11
David Villa's signing and the emergence of Sergio Busquets alongside the established guard led the club to another Champions League victory.
Barcelona's squad 2011-12
After years of flirtation, Cesc Fabregas finally made his return to the Camp Nou from Arsenal although, naturally, they struggled to replicate the form of the previous campaign.
Javier Mascherano would also swap the Premier League for La Liga in a huge deal, though would be moulded into a central defender alongside Pique.
For the first time, Eric Abidal had been replaced at left-back by youngster, Adriano.
Alexis Sanchez would provide another squad option.
Barcelona's squad 2012-13
The left-back issue was addressed as Jordi Alba moved across from Valencia to complete the dream team.
Barcelona's squad 2013-14
Neymar's first season did not yield much in the way of success as Real Madrid won the Champions Lague and Atletico Madrid lifted La Liga.
Barcelona's squad 2014-15
Barcelona's most recent successful recruitment drive.
Another treble was secured after the signings of Luis Suarez, Ivan Rakitic and Claudio Bravo to refresh a squad that had been together for so long.
Xavi's final season.
Barcelona's squad 2015-16
Barca remained the dominant team in La Liga but, PSG comeback aside, the fabled 'MSN' attacking frontline could not manage to win another Champions League title.
Largely, the playing staff remained the same but the end of the season saw Alves depart.
Barcelona's squad 2016-17
A poor recruitment drive failed to back up the first-team.
None of Lucas Digne, Andre Gomes or Paco Alcacer ever truly proved their worth and, while Samuel Umtiti did enjoy more of a first-team role, even the Frenchman was an obvious downgrade.
Barcelona's squad 2017-18
Reeling from the departure of Neymar, a right-back was never signed to replace Alves, meaning Sergi Roberto had to continue in the unfamiliar role.
Iniesta would leave at the end of the season, depriving Barca of two of their greatest modern players.
Barcelona's squad 2018-19
A season remembered for the loss to Roma in the Champions League despite leading the quarter-final by some distance at the halfway point, Clement Lenglet and Coutinho were two of the newer faces in the first-team.
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Strong enough in the league but, sadly, the decline was starting to worsen.
Barcelona's squad 2019-20
Arturo Vidal never seemed a natural fit at Barcelona and, after the relatively stable Ernesto Valverde reign had ended, things seemed to collapse for both him and the team.
Mauled in the Champions League by Bayern Munich, Messi would soon ask to leave.News Now - Sport News