Only Atletico Madrid have matched Gerardo Martino's side so far, with Real Madrid two points back in third.
Barcelona have been in devastating form at the start of the campaign, scoring 18 goals in their opening five matches while only conceding four.
They emphatically won this fixture 5-1 last season but Sociedad got their revenge in January and became only the second side to beat Barca in the league, prevailing 3-2.
Cesc Fabregas will not feature for Martino's side after he was left out in order to have a rest, with Sergio Busquets coming in having missed the win over Rayo Vallecano.
Carles Puyol remains sidelined as he continues his rehabilitation from knee surgery.
Atletico will hope to keep pace with Barcelona when they face Osasuna at the Vicente Calderon.
Diego Simeone's side are unbeaten in their last seven meetings with Tuesday's opponents and they will hope that Diego Costa continues his rich vein of form to fire them to victory.
The Brazilian striker has found the back of the net five times this season, with only Lionel Messi scoring more.
Their city rivals Real Madrid travel to struggling Elche on Wednesday for their first meeting since 1989.
Carlo Ancelotti's side will be without world-record signing Gareth Bale (groin) but may have Iker Casillas and Sergio Ramos available after both men returned to training on Monday.
Madrid will be hoping to avoid a repeat of the last time they met a promoted side – they were were held to a 2-2 draw by Villarreal.
Marcelino Garcia Toral's side have made an excellent start on their return to the top flight and will look to continue that when they face Espanyol.
Like their opponents, Espanyol have started the season well, and have also yet to taste defeat this season.
Real Betis travel north to Bilbao to become the second side to face Athletic at their new San Mames Barria stadium.
Athletic won their first game in the new stadium against Celta Vigo but they have not beaten Betis in their last four attempts so will be wary of Pepe Mel's side.
Valencia put a disappointing performance in Europe behind them on Sunday with a win over Sevilla and the under-pressure Miroslav Dukic will hope that they can repeat that form when they travel to Granada.
Elsewhere, Levante welcome Real Valladolid to the Estadio Ciudad de Valencia on Tuesday, while Almeria travel to Malaga on Wednesday.
Rock-bottom Sevilla go in search of their first win of the season against Rayo Vallecano, and Getafe entertain Celta.
