Lionel Messi scored a hat trick and Luis Suarez added two more goals to help Barcelona rout Rayo Vallecano 6-1 at home and take the lead of the Spanish league on Sunday.
Barcelona capitalized on Real Madrid's latest slip to move one point ahead at the top of the table with the fierce rivals set to meet at Camp Nou in two weeks.
Luis Suarez got Barcelona going in the sixth minute before Gerard Pique tapped in a ball Jordi Alba had headed off the post four minutes after halftime.
Messi's treble in a 13-minute span came after he missed his second penalty in as many weeks following Roberto "Tito" Triguero's sending off with a second booking. But the referee ordered the spot kick to be repeated, and the Argentine wasn't denied a second time.
He then struck twice more to equal Cristiano Ronaldo's competition-leading tally of 30 goals in 26 rounds. Ronaldo had once looked set to run away with the league's individual scoring title when he led Messi by a margin of 25-13 goals through 15 rounds.
Barcelona also finished with 10 men when Dani Alves saw red for fouling Alberto Bueno, who converted the late penalty.
Suarez scored again in stoppage time for his sixth goal in his last four appearances, as the former Liverpool striker finds his stride in time for crucial upcoming matches against Madrid in the league, Manchester City in the Champions League and a Copa del Rey final against Athletic Bilbao.
"Suarez plays well with Messi and is giving us more and more," said Barcelona coach Luis Enrique. "It's clear they have a special connection. When you put players of their talent together it gives us many more options in attack."
Barcelona returned to lead the standings for the first time since the ninth round, over four months ago.
"We have gotten to where we are by playing each game as it comes," said Luis Enrique. "But only one team will win the Copa and only one will win the league, the same with the Champions League, so we have to be prudent and remember there are rivals trying to achieve the same thing."
Luis Enrique said that Neymar wasn't in the squad for Sunday's game because he had been given permission by the club to return home to Brazil.
Rayo coach Paco Jemez had said before the match that he didn't care if his team "lost by one or seven goals."
And his side paid a heavy price for staying true to its risky style of playing a high defensive line, which often leaves its goalkeeper Cristian Alvarez to act as a sweeper and fend for himself.
Despite the lopsided loss, Jemez said he was "satisfied" with his team's effort as it stayed in 11th place.
"What doesn't work to beat Barcelona, Madrid or Atletico will work against other opponents," Jemez said.
Suarez's first goal was a beautiful strike using the tip of his right boot to power the ball beyond Alvarez after Xavi Hernandez had played him through.
Messi had a spot kick saved by Alvarez a week after City 'keeper Joe Hart blocked his try, but this time he was able to retake the penalty and drove in Barcelona's third goal in the 56th.
The Argentina forward was well placed to finish off Alvarez's save of Suarez's shot in the 62nd, and six minutes later he dribbled the goalkeeper to roll in his third.
Barcelona's big win came a day after Madrid lost 1-0 at Bilbao. That defeat followed a home draw against Villarreal, meaning Madrid has dropped five of the last six points in play.
Later, third-place Atletico Madrid hosts fourth-place Valencia, Villarreal welcomes Celta Vigo, and Espanyol visits Real Sociedad.