The result means that Gerardo Martino's start to life at the Catalan club has been the best beginning to a new manager’s reign in Barcelona history, with six wins from a possible six and a plus-17 goal difference.
Neymar opened the scoring five minutes in against Sociedad as he capitalised on poor defending to tap home Alexis Sanchez’s low cross and net his first La Liga goal, while Lionel Messi doubled the advantage a few moments later with a diving header after good wing play by the Brazilian.
Sergio Busquets made it 3-0 before 30 minutes had been played, firing a half-volley into the bottom of the net from outside of the area.
Alberto De La Bella pulled on back as he knocked Imanol Agirretxe’s poked cross into an empty net, but Marc Bartra restored the three-goal lead 13 minutes from time as he diverted Messi’s low delivery past Bravo.
Atletico also racked up their sixth league win of the campaign as they defeated Osasuna 2-1 at Vicente Calderon.
Diego Costa has been the star for them so far this season, and Tuesday was no different. The Brazilian placed Juanfran’s cross into the bottom corner before heading Koke’s delivery past Andres Fernandez.
Oriol Riera stuck out a foot to direct Francisco Punal's free-kick past Thibaut Courtois, but Osasuna were unable to salvage anything from the game.
Levante were unable to make a significant move up towards the top four as they drew 1-1 at home to 10-man Real Valladolid, leaving them in eighth.
On-loan Sevilla forward Baba Diawara opened the scoring in the 36th minute, his first La Liga goal since May 2012, but Levante's lead did not last long as Javi Guerra equalised a few moments later.
Zakarya Bergdich was shown red card a minute before the break, but Levante could not make the most of their chance as Andreas Ivanschitz's resulting penalty was saved.
Malaga moved above a host of clubs thanks to their 2-0 home win over Almeria.
The Andalucian side played out a goalless first half, but Fernando Tissone found the net after 68 minutes before the hosts scored a second in stoppage time thanks to Francisco Portillo.
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