Barcelona were the better side for most of the match after that, but scored only once thanks to a superb counter-attack from man of the match Dembele in the 52nd minute.
The electric winger ran through the right channel after receiving a precisely placed long pass from his France teammate Jules Counde and fired an unstoppable right-footed strike into the top corner.
Sociedad should have equalized seven minutes later, but Alexander Sorloth missed a sitter, skyrocketing a shot from inside the six-yard box from a Kubo cross.
After Gavi’s volley against the crossbar from a great cross by Dembele in the 68th minute, Real made a late push and could have scored on at least three occasions, with Barca keeper Marc-Andre ter Stegen pulling off the winning goal. Took many efforts for this.
“After being one-man down it was a struggle for us because they closed well and defended consistently,” Barca defender Ronald Araujo told Movistar Plus.