The 21-year-old Neymar, seen as one of the brightest prospects in soccer, announced on Saturday he had picked Barca over Real and would be leaving Santos to sign a five-year deal with the Catalan club.
As well as a gifted athlete, Neymar is a massive global celebrity and linking up with Barca's Argentine World Player of the Year Lionel Messi will guarantee spectacle on the pitch as well as a huge boost to the club's marketing profile.
Barca recaptured their La Liga title from Real this season but fell in the semi-finals of the Champions League and Neymar will also help rejuvenate a squad in which leading figures like David Villa, Carles Puyol and Eric Abidal are nearing the end of their careers.
Real, by contrast, are in disarray after a season without major silverware that prompted the club and coach Jose Mourinho to agree to part ways.
Construction magnate Perez is up for reelection next month and while he looks for a replacement for Mourinho, Real's members, who own the club and choose the president, will be expecting him to unveil a signing to match Neymar's.
Reports in Spain have said Perez is targeting Tottenham Hotspur's Wales winger Gareth Bale, and that Atletico Madrid's Colombia striker Radamel Falcao and Malaga's Spain playmaker Isco are also on his wish list.
The snaring of Bale, valued at 42 million euros ($54 million) on transfermarkt.com, or Falcao, valued at 60 million, would help ease the pain of a difficult season.
It would also boost the fans' hopes that Real, the world's richest club by income and the nine-times continental champions, can return to the summit of the game.
Real have spent more than 400 million euros on players since Perez returned to the presidency in 2009, including a record 94 million euros on Cristiano Ronaldo.
In that time, their haul of major trophies has been one La Liga title and one King's Cup, a meagre return on investment.
Perez, who has been credited with transforming Real into the world's biggest-earning sports club, was forced to abandon the presidency in 2006 after his "galacticos" project foundered and the fans turned against him.
He is unlikely to be challenged at next month's elections but if he is unable to get the better of Barca, restore Real's prestige and, most importantly, bring titles to the club, he may have to walk away again.
($1 = 0.7734 euros)
- Sports & Recreation
- Lionel Messi
- Jose Mourinho