Javier Mascherano scored his first-ever Barcelona goal as the Catalans dismantled Osasuna 7-1 to stay top of La Liga and relegate the visitors.
Mascherano netted from the penalty spot and Lionel Messi, Paco Alcacer and Andre Gomes all scored braces as Barca temporarily opened a three-point lead on Real Madrid.
The Blaugrana made five changes from the side that defeated Madrid in the Clasico last Sunday, including resting Luis Suarez, who was without a goal in five matches.
Alcacer led their attack in the Uruguayan’s absence, while there were also starts for Lucas Digne, Denis Suarez, Andre Gomes and Arda Turan.
Osasuna would be relegated back to the Segunda Division if they lost at Camp Nou and Leganes beat Las Palmas later in the evening.
Just as the Pamplonans came out of their shell, Messi dashed past last man Jhon Mondragon and lobbed Salvatore Sirigu to make it 501 goals in Barca colours.
The Argentine proved he was human after all as Alcacer flicked the ball back into the Osasuna box for his superstar teammate, who volleyed well over from close range.
Yet moments after Salvatore Sirigu saved Messi’s low shot from around 20 yards out, Ivan Rakitic’s cutback was blasted home by Gomes.
Arda then won a free kick to the left of Osasuna’s box, and Messi's set-piece was looped on target by Alcacer’s head, only for Sirigu to tip the ball around the post.
Barca paid the price for a slow start to the second half as Sergio Busquets conceded a sloppy free kick just outside the Barca box, and it was curled into Marc-Andre ter Stegen’s top-left corner by Roberto Torres.
Javier Mascherano had yet to score for the Catalans after 319 appearances, and the Argentine was prevented from opening his long-awaited account by Sirigu, who pushed his header onto the post.
Osasuna almost netted a shock second as a delicious ball made its way past Ter Stegen and dropped for Torres at the far post, but the attacking midfielder’s thunderous half-volley was punched away by the goalkeeper.
Nonetheless, normal service was resumed when Gerard Pique’s chest-and-volley was kept out by Sirigu and Gomes made no mistake from the rebound as he drove it hard and low past the Italian.
Messi then surged through the middle, before veering left, curling an unstoppable strike past Sirigu and being replaced by La Masia starlet Carles Alena to a standing ovation.
Alcacer rounded Sirigu from a through ball and lifted a sliding finish over the goalkeeper for 5-1, but Camp Nou’s roof only came off once Mascherano blasted a penalty into the roof of the former Sevilla man’s net after Denis Suarez was tripped in the Osasuna box.
Alena showed plenty of nice touches and impressive composure on the ball during his cameo, and the midfielder curled a shot just over.
The rout was settled by Alcacer, who skipped past Sirigu and finished into an empty net to leave Barca in seventh heaven – and make Osasuna the first club in Europe’s top five Leagues this season to drop a division.
Barcelona 7-1 Osasuna
Messi 12, 61, Gomes 30, 57, Alcacer 64, 86, Mascherano pen 67 (B) Roberto Torres (O)
Barcelona: Ter Stegen; Pique, Mascherano, Digne; Rakitic, Busquets, Gomes, Denis; Messi (Alena 63), Alcacer, Arda
Osasuna: Sirigu; Bunuel, Oier, Steven, Fuentes; Jaime (Olavide 72), Merida (Causic 79), Tienza, De las Cuevas, Roberto Torres; Sergio Leon (Kodro 73)
Referee: Martinez Munuera