The 62-year-old Mazzarri became the second man to be sent packing this season by the ailing Italian champions.
Girona defeated their Catalan rivals for the first time ever in the top flight in a pulsating battle to rise two points above Real Madrid, second, after their 1-1 draw at Real Betis on Saturday.
Champions Barca were dominating the match early on under the scorching heat of south Madrid, with Brazil winger Raphinha the main threat to the home side's defence by running the right channel and creating several opportunities.
Barca's friendly against Juventus, due to be played later on Saturday, was cancelled after an outbreak of viral gastroenteritis among the Spanish team
Xavi's side wrapped up the title after two first-half goals from Robert Lewandowski spurred them to a 4-2 win against city rivals Espanyol on Sunday
UEFA opened a formal investigation into Barcelona last month for potential violation of the European soccer governing body's legal framework regarding payments made by the club to a company owned by a senior refereeing official
Barcelona beat Real Madrid 1-0 in the Copa del Rey semi-final first leg on Thursday at the Santiago Bernabeu, but were criticised for only having 34 percent possession
Fernandes told BT Sport. "The belief of the fans, they push us through difficult moments. We have made great comebacks, the club is made also by that. In the past we have done a lot like this result"
Mexico's Pumas on Saturday signed Dani Alves after the veteran Brazilian defender left Barcelona for a second time.
Barcelona striker Neymar’s father confirmed that Manchester United had tried to lure the star to the Premier League, but the offer was dismissed.
Former Real Madrid goalkeeper Iker Casillas has labelled Barcelona star Lionel Messi the opponent he has had the most difficulty facing.
Pressure on Neymar and Suarez grow with each match as Barcelona look to regain momentum and head the La Liga without Messi in their ranks.
German football idol Lothar Matthaus has thrown his weight behind Lionel Messi to win the 2015 Ballon d'Or, insisting that no-one else merits the award.
Barcelona striker Luis Suarez says he feels "responsibility" to try and compensate for the loss of Lionel Messi during his injury layoff.
Zinedine Zidane has voiced his admiration for Cristiano Ronaldo and believes the rivalry with Barcelona ace Lionel Messi only spurs on the Real Madrid attacker.
Neymar believes Lionel Messi, Luis Suarez and himself were always going to be a success for Barcelona.
Lionel Messi posted a cryptic Instagram message on Friday as he continues his recovery from a knee injury.
Ivan Rakitic has labelled Barcelona team-mates Lionel Messi, Luis Suarez and Neymar "football magicians".
A Barcelona side without the injured Lionel Messi head to face Sevilla at Estadio Ramon Sanchez Pizjuan on Saturday, desperate to move back to the summit of La Liga.