Lewandowski suffered a back injury in Sunday's 1-0 defeat at Real Sociedad during which he had a goal controversially disallowed.
Lewandowski's early disallowed strike led to furious debate over whether the Polish forward had been offside or not.
It was another commanding victory for LaLiga leaders Barcelona who are in an imperious vein of form, scoring 24 goals in six successive wins in all competitions, including thrashings of Bayern Munich and Real Madrid.
Madrid beat Celta Vigo on Saturday to pull level with Hansi Flick's side but Barca swiftly restored their advantage with a stylish and dominant display of attacking football.
The 36-year-old hitman looks far sharper than last season and has 12 goals in 11 games across all competitions.
The Polish forward struck from close range in the first half to maintain Barca's 100 percent record in the league so far this season with their seventh victory.
Barcelona striker Robert Lewandowski would love Lionel Messi to return to the Catalan club from Paris Saint-Germain this summer, he said on Tuesday.
La Liga is reportedly refusing to allow FC Barcelona to register new players ahead of the new season.
Bayern Munich star Robert Lewandowski revealed Tuesday he wants to call time on his career with the Bundesliga giants because of his desire for "more emotions in life".
Robert Lewandowski scored a brilliant free kick to give Bayern Munich a 1-0 win over Atletico Madrid in their last Champions League Group D outing on Tuesday, ending the 100 percent record of their opponents.
German newspaper Bild reports that Borussia Dortmund defender and captain Mats Hummels is in talk with Bundesliga rivals Bayern Munich over a possible move there after his contract expires in 2017.