Ernesto Valverde's side are top of the Primera Division and are still unbeaten at the halfway stage with 51 points, but the Blaugrana lost 1-0 to their city rivals in the first leg of the teams' Copa del Rey quarter-final on Wednesday.
That was Barca's first loss since double defeat to Real Madrid in the Spanish Supercopa in August and they will look to overturn the deficit in the return at Camp Nou next week.
Before that, Barca are in action away to Betis and here, Goal takes a look at everything you need to know ahead of their trip to Seville on Sunday...
Recent recruit Philippe Coutinho is out for around 20 days with a minor problem and will have to wait for his debut, while summer signing Ousmane Dembele is also missing after picking up another injury in the 4-2 win at Real Sociedad last weekend.
Paulinho and Andres Iniesta are carrying knocks and are doubtful, as are Samuel Umtiti, Paco Alcacer and Javier Mascherano.
Valverde has no players suspended for the trip to the Benito Villamarin on Sunday.
BARCELONA POTENTIAL STARTING LINE-UP
Andres Iniesta and Paulinho will start in midfield for Barcelona if they are passed fit for this weekend's trip to Andalucia.
With Dembele sidelined, Rakitic will likely feature on the right for the Blaugrana, while Sergi Roberto looks set to start at right-back after signing a new contract this week.
Yerry Mina, who was signed from Palmeiras last week for €11.8m, will have to wait for his debut, as will the injured Coutinho.
BETIS TEAM NEWS
Zouhair Feddal and Aissa Mandi return from suspension and should start for Betis against Barca in the centre-back positions on Sunday.
Forwards Joel Campbell and Antonio Sanabria miss out through injury, along with right-back Antonio Barragan.
Betis have had an extraordinary season so far. The Andalusians are in seventh place, two points behind Sevilla, and have won their last two games in La Liga (a 5-3 win in the city's derby at the Sanchez Pizjuan and then a 3-2 victory at home to Leganes last weekend).
TV COVERAGE & KICK-OFF TIME
Betis versus Barcelona kicks off at 20:45 local time at the Benito Villamarin on Sunday and will be broadcast live in the UK on Sky Sports Football from 19:40GMT.
In the United States, the game can be watched live on television on beIN Sports and kicks off at 14:45ET.
BEST OPTA MATCH FACTS
Barcelona are unbeaten in La Liga this season, this being the third occasion in the last nine campaigns that they have got to this stage without suffering a single loss (also in 2009-10 and 2012-13).
Betis have won three of their last four La Liga matches, losing the other. However, they have only won one of their last five at home.
Barcelona are unbeaten in their last 13 La Liga matches against Betis (won 10, drawn three), and could equal their best run against them in the competition (14, between 1943 and 1964).
Betis have not kept a clean sheet against Barcelona in La Liga since September 2002.
If Messi provides an assist in this game, he will have set up a team-mate in five consecutive La Liga matches for the first time in his career. And if he scores and assists, he will have both scored and assisted in four consecutive La Liga games for the first time ever.