Lionel Messi scored before being substituted due to injury to help Barcelona win 2-0 at Almeria on Saturday and set a club record with a seventh straight victory to start the Spanish Primera Division.
Messi netted his league-leading eighth goal to open in the 21st minute, but he asked to be replaced eight minutes later after hurting a muscle in his right leg.
Adriano sealed the result in the 56th from a pass by Cesc Fabregas while Messi watched from the bench.
Messi's injury leaves him in doubt for Tuesday's Champions League match at Celtic.
While Barcelona may be missing Messi for the trip to Glasgow, it should have Neymar well rested after the striker didn't play a minute at Juegos Mediterraneos Stadium.
Barcelona's first-year coach Gerardo Martino has guided Barcelona to their best start in 82 leagues. Five other managers, including Pep Guardiola (2009-10) and predecessor Tito Vilanova (2012-13), had reached six wins.
Elsewhere, Jonas scored his third winning goal for Valencia this week to secure a 1-0 victory at home over Rayo Vallecano.
The Brazilian forward netted the decisive goal in recent wins against Sevilla and Granada, and he stepped up once again to produce the 36th-minute winner after intercepting a poor pass by Rayo's Saul Niguez.
The promoted, and winless, Almeria did well to hold their own against the defending champions early on.
But after goalkeeper Esteban Suarez swatted Andres Iniesta's shot over the bar, it took Messi only a burst of speed and a quick one-two passing combination with Pedro Rodriguez to open up an angle and curl a left-footed shot off the post and into the net.
Messi's celebration was short-lived, however, when he asked to be substituted following an injury to his right thigh incurred during a long sprint to pressure Suarez. Messi has already missed one game this season with a left thigh bruise and several games at the end of last season due to a right hamstring pull.
The club said the Argentina forward would undergo more tests on Sunday.
Without Messi or Neymar, Barcelona struggled in attack and Almeria pressed the visitors into their area before the halftime whistle.
Barcelona regrouped during the break and Adriano redirected Fabregas' low cross home to complete a move started by Xavi Hernandez, who replaced Messi, and finish off any thoughts of an Almeria rally.
Little-used Marc Bartra played well in Barcelona's defence with veterans Javier Mascherano and Carles Puyol injured.