A Luis Suarez double sealed the comeback win for Barca after Inter had led through Lautaro Martinez’s early goal.
Lautaro Martinez scored in the 2nd minute of the game but the Blaugrana responded after half time with two brilliant finishes from Uruguay hitman Suarez.
The second goal for Barca came just 6 minutes before the end of the game as Antonio Conte suffered his first defeat of the season.
Inter, without the injured Romelu Lukaku, had lost their last four games in Barcelona, yet they made a fine start courtesy of Martinez.
The striker latched onto ex-Barca forward Alexis Sanchez’s through-ball and, under pressure from Gerard Pique, fired across Marc-Andre Ter Stegen into the bottom corner.
Barcelona came into the game, having a spell of pressure, and Antoine Griezmann rose highest to head Sergi Roberto’s cross just over after a fine move.
Sergio Busquets then side-footed over from the edge of the box.
Inter continued to be a threat on the break, though, and had chances to score again.
Antonio Candreva got round the back of Nelson Semedo, controlling an exquisite long ball and firing through the defences of Ter Stegen, only to see the offside flag raised.
Semedo was then in the right place at the right time to produce a goal-saving block and deny Nicolo Barella, before Ter Stegen produced a fine diving save to keep out a powerful Martinez header.
After Stefano Sensi curled over for Inter, Barca stirred into action just before half-time, with Lionel Messi’s free-kick from distance easy for Samir Handanovic and Arthur slicing a shot over.
The hosts came out firing in the second half and took just 13 minutes to draw level.
Arturo Vidal, on as a 53rd-minute substitute for Busquets, lofted a ball to Suarez and the striker smashed a stunning low volley into the bottom corner from the edge of the box.
Griezmann fired into the side-netting from close range before making way for fellow Frenchman Ousmane Dembele while Sanchez, taken off 10 minutes earlier, and Conte received bookings for dissent in the dugout.
Messi had a hand in the winner in the 84th minute, running at the Inter defence and laying off to Suarez, who breezed past Diego Godin and slid the ball past Handanovic.
Absolute scenes were witnessed at Camp Nou as one commentator displayed the sheer power in his lungs as he went into a manic celebration after Barcelona’s winner –