Fourth-placed Valencia moved to within a point of Real Madrid with a 2-0 win over Real Betis in La Liga on Sunday.
Rodrigo finished off a quick counter-attack to fire the hosts ahead after 23 minutes.
Shortly after the restart, Simone Zaza latched onto a through-ball from Geoffrey Kondogbia to double Valencia's advantage and wrap up the three points.
At the other end of the table, it was not such a good day for Levante and their coach Juan Ramon Lopez Muniz, who was sacked in the wake of their agonising 1-1 home draw with Espanyol.
Levante midfielder Jose Morales looked to have earned the hosts a precious three points, converting a 55th-minute penalty after Marc Navarro pulled down Erick Cabaco.
But Espanyol - who beat Real Madrid in midweek - had the final say when Brazilian forward Leo Baptistao swept home Jose Manuel Jurado's cross in the first minute of stoppage time.
That denied Levante a first win in 15 La Liga games and resulted in promotion-winning coach Muniz's departure.
Real Sociedad put more clear water between themselves and the relegation zone with a 2-1 win over Alaves.
Hector Moreno opened the scoring after just six minutes when he netted from close range from a Sergio Canales corner.
Asier Illarramendi made it 2-0 five minutes later, tucking away the rebound after Alaves keeper Fernando Pacheco pushed Jon Bautista's shot into his path.
Alfonso Pedraza pulled one back before half-time when he dispatched Martin Aguirregabiria's cross, but Alaves could not find an equaliser.
Lionel Messi scored his 600th career goal as Barcelona landed what could be the knock-out blow in this season's La Liga title race with a 1-0 win over nearest challengers Atletico Madrid.
Messi reached yet another milestone - 539 goals for Barca and 61 for Argentina - when he curled a brilliant 25-yard free-kick into the near top corner of Jan Oblak's net after 26 minutes.
That proved to be the only goal of the game at the Nou Camp and a fitting way to settle the top-of-the-table encounter as Barca moved a significant step closer to reclaiming the Spanish title.
Ernesto Valverde's men are now eight points clear of Atletico - while also boasting the better head-to-head record against the Rojiblancos should it somehow still come down to that - and a massive 15 points above defending champions Real Madrid in third.
With only 11 games to go after this round and Barca having only lost once in 42 competitive games since the start of their league campaign, it looks like it would take something remarkable for the Blaugrana to now be denied the title.