Lionel Messi and Luis Suarez scored first-half goals in a 3-0 win over Levante on Sunday, restoring Barcelona's nine-point lead of the Spanish league while it awaits the arrival of Philippe Coutinho.
Messi marked his 400th appearance in La Liga by giving Barcelona the early lead and taking his all-time record in the competition to 365 goals.
Suarez doubled the advantage before halftime and Messi set up Paulinho to round off the win in stoppage time.
Such an emphatic victory comes as Barcelona's attacking threat is preparing for an additional injection of creativity with the 25-year-old Coutinho.
The Camp Nou is anticipating the incorporation of the Brazil midfielder, who flew to Barcelona on Saturday. Barcelona said Coutinho has yet to meet with his new teammates and coach, although he did make an appearance at the stadium for a photo session after Sunday's match.
"This is like living a dream," Coutinho told the club's website. "It's incredible to know that I am going to play with my idols, players who have made history. Players like Leo Messi, Luis Suarez, (Andres) Iniesta, (Gerard) Pique, (Sergio) Busquets... I am happy to be able to live with and learn from them, and to win titles."
Coutinho will be officially presented Monday after a transfer deal that could reach 160 million euros ($192 million).
"(Coutinho) is a player who I think can bring many things to the team," Barcelona coach Ernesto Valverde said. "He scores goals and provides assists, and in attack he can help us a lot."
Not that Barcelona needs it in the league. Atletico Madrid, which beat Getafe 2-0 on Saturday, remains a distant second, and fourth-place Real Madrid stumbled again on Sunday when it drew at Celta Vigo 2-2.
The win took Barcelona's unbeaten streak to 27 straight matches.
Ousmane Dembele started for Barcelona and played just more than an hour before being substituted in his second appearance since returning from a left-leg injury that sidelined him since mid-September. The 20-year-old France forward played the final minutes of Thursday's 1-1 draw at Celta Vigo in the Copa del Rey.
"In these three months I have been able to learn Barcelona's philosophy, now I am eager to help the team," Dembele said.
Until the deal for Coutinho, Dembele was the club's most expensive signing for a transfer fee of 105 million euros that could rise to 147 million euros.
Messi once again this season connected with left-back Jordi Alba, who headed back his pass for the Argentine forward to use one touch to volley in off the far post in the 12th minute and record his league-leading 16th goal of the season.
Javier Mascherano started for Barcelona amid widespread speculation that he wants to leave in search of more playing time.
The defender helped to set up Barcelona's second goal by lobbing a pass over Levante's defence where Sergi Roberto used one touch to send it to Suarez in the 38th. The striker controlled the ball with his left foot before sweeping home with his right for his 11th goal of the season and his sixth in a five-round scoring streak.
After Barcelona goalkeeper Marc-Andre ter Stegen made two superb saves, Messi effectively finished the match by dribbling to the end line before squaring a pass for Paulinho to tap in for his seventh goal of the season.
Barcelona reserve-team striker Jose Arnaiz debuted in the league as a late substitute.
16 POINTS BEHIND
Real Madrid wasted a brace by Gareth Bale as it fell further behind the top three teams after drawing at Celta.
Bale's two goals in a three-minute span in the first half overturned an opener by Celta's Daniel Wass.
But they weren't enough for the win amid an uninspiring performance by Cristiano Ronaldo, and poor defending by Marcelo and the rest of Madrid's backline.
Celta outplayed Madrid in the second half and its defenders left unmarked striker Maxi Gomez to head in a pass by Wass for an equalizer in the 82nd.
Celta's Iago Aspas went close to scoring twice, hitting the post early and having a penalty kick saved by Keylor Navas after the goalkeeper had fouled him in the 71st.
The result left Madrid 16 points behind Barcelona, although with a match in hand, after only managing to win three of its last eight league games.
"I have to find out what the problem is," coach Zinedine Zidane said. "Sometimes we play 90 minutes well, but it is true that recently we don't do it regularly. We need to have more confidence in our chances, and recently we don't have the confidence to play 90 minutes well."
(With AP Inputs)