The Brazilian bundled home Alexis Sanchez's cross after just five minutes and then expertly teed-up Lionel Messi to plant a diving header past Claudio Bravo three minutes later.
Sergio Busquets added a third before half-time with a sweet strike from 20 yards to register his first goal of the season as the home side produced their best 45 minutes of the season to date.
Alberto De la Bella reduced the arrears for Real Sociedad midway through the second half, but Messi crossed for Marc Bartra to round off the scoring 14 minutes from time as Barca scored four for the third consecutive game.
Amazingly, the visitors had made the brighter start with Haris Seferovic striking the bar from 20 yards inside two minutes. However, the game was virtually lost for them just six minutes later.
Firstly, a horrible defensive mix-up between Liassine Cadamuro and Bravo allowed Neymar to bundle home his first and possibly the easiest goal he will ever score for Barca at the Camp Nou.
And three minutes later the Brazilian delivered a perfect left-footed cross from which Messi headed home at the far post. Bravo had to rush from his line to prevent Neymar scoring his second of the evening moments later as Barca threatened to run riot.
And things went from bad to worse for Real when captain Xabi Prieto had to be replaced by Imanol Agirretxe with a muscular problem that will make him a serious doubt for their Champions League trip to Bayer Leverkusen next week.
It didn't take the hosts long to register their third of the evening, however, as Messi's backheel was well saved by Bravo, the Argentine's follow-up effort somehow hit the bar and post on its way out and Busquets finally fired home the rebound from outside the area.
Barca had an injury blow of their own to deal with as Javier Mascherano came off with a hamstring problem to be replaced by Bartra 10 minutes before the break.
However, the hosts were still in full flow and nearly produced a goal of the season contender as Messi, Xavi, Andres Iniesta and Neymar all combined inside the area before Messi unbelievably failed to connect properly on his left foot to turn Neymar's cut-back home.
Messi wasn't having his best night in front of goal as he blasted another glaring opportunity over the bar after accelerating past three defenders at the beginning of the second period.
Real were then given a glimmer of hope when Agirretxe did well to hold off Gerard Pique and square for De la Bella to tap home 26 minutes from time.
However, Barca's three-goal advantage was restored 12 minutes later when Messi wriggled his way towards the by-line and his low cross was guided home by Bartra.
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