Barcelona will complain to the Royal Spanish Football Federation [RFEF] after they were denied a late penalty in Saturday's 2-2 draw at Real Sociedad, sources have told ESPN.

Gerard Pique appeared to be pulled down in the area in the 93rd minute of the game but referee Antonio Alberola Rojas turned down Barca's appeals. The decision didn't even appear to be referred to VAR.

Real Sociedad had earlier been awarded a penalty in very similar circumstances when Sergio Busquets tangled with Diego Llorente.

Barca president Josep Maria Bartomeu felt both penalty calls should have been looked at by VAR and was left so unimpressed with events in San Sebastian that he contacted his counterpart at the RFEF, Luis Rubiales, immediately after the match.

Bartomeu will now proceed to file a formal complaint about the use of VAR to the RFEF on Sunday. He will also ask for an explanation about how the technology is being applied in Spain, pointing out that Barca were among those who supported its introduction into La Liga.

Mikel Oyarzabal's early penalty had given La Real the lead but Barca fought back with goals from Antoine Griezmann and Luis Suarez.

The home side levelled just after the hour mark through Alexander Isak and both sides had chances to win the game, but it was Barca who were left unhappy as their late penalty shout fell on deaf ears.

"There's always going to be controversy," midfielder Busquets told reporters. "For their penalty, there's a clash [between two of us]. Maybe I have grabbed [Llorente] but if you set the bar there it's going to be difficult [to remain consistent].

"The proof of that comes with Pique, because it's clearer than mine. I don't know why VAR didn't review it. Those moments have to be looked at by VAR.

"But we don't know what's going on in the referee's head or when VAR should get involved. We don't know and we're not going to know because they don't say. They don't make any comments [about the decision process]."

The draw could see Barca give up top spot to Real Madrid if Los Blancos can win away at Valencia on Sunday.

Barca and Madrid then meet on Wednesday at Camp Nou in the first Clasico of the season, a game which has been rearranged having been called off in October due to the political unrest in Catalonia at the time.