Midfielder Pedri earned Barcelona a tense 1-0 Catalan derby victory at Girona on Saturday, opening a six-point gap over Real Madrid at the top of La Liga.
With Carlo Ancelotti's side hosting high-flying Real Sociedad on Sunday, Barca put their rivals under pressure to get a result and keep up in the title race.
Pedri netted the only goal from close range after an hour at an icy Montilivi on his 100th appearance for Barcelona, after replacing the injured Ousmane Dembele.
The French forward limped off in the first half, pulling up after a sprint and asking to be replaced, a blow for Barcelona considering his superb recent form.
Barca coach Xavi handed Eric Garcia a rare start, along with Marcos Alonso, who extended his contract until 2024 on Friday.
The league leaders were still without suspended Polish striker Robert Lewandowski, missing his final game after a three-match ban.
Girona created the first chance after just three minutes, Rodrigo Riquelme's smooth through ball feeding Yan Couto, whose shot was blocked.
Dembele also had an effort deflected away at the other end after Ansu Fati won the ball from goalkeeper Paulo Gazzaniga.
The French winger, who fired Barcelona into the Copa del Rey semi-finals against Real Sociedad in midweek, was forced off injured after 25 minutes with Pedri replacing him.
Fati lashed over after pressing high to win the ball back as Barcelona failed to find their rhythm in attack.
Xavi brought on Jordi Alba for Alonso at the break and it made the difference for Barcelona.
The left-back set up Pedri's opener with a cross from the left, tapped in by the Spaniard at the back post at the end of the first incisive move Barca had put together all game.
The midfielder, whom Xavi had intended to rest, reached a century of appearances for Barca at just 20 years old and celebrated with his 15th goal for the club.
Ronald Araujo headed a cross off his own goal line under pressure as Girona pushed for an equaliser, throwing men forward.
Ivan Martin missed a fine chance in stoppage time for the hosts as Barcelona lost all control of the game but survived a nervy finale to earn the win.
The Catalans have conceded just six goals in La Liga this season and Girona, 11th, could not find the seventh to snatch a point.
Girona coach Michel was sent off in stoppage time with a direct red card for vehemently protesting what he thought was a foul on one of his players.
