Madrid: Luis Suarez scored a hat-trick as Barcelona came from behind in the absence of the injured Lionel Messi to beat Basque minnows Eibar 3-1.
Victory takes Barca level with Real Madrid on 21 points, but Los Blancos remain on top thanks to their superior goal difference.
Atletico Madrid moved up to third, two points behind the leaders, thanks to goals from Jackson Martinez and Yannick Ferreira Carrasco in a 2-1 win over Valencia on Sunday.
The on-form Borja Baston fired Eibar into a shock lead just 10 minutes in at the Camp Nou, but Suarez restored parity with a bullet header and then put Barca in front just after the break.
Eibar were handed a lifeline when Javier Mascherano saw a straight red card for protesting with the referee seven minutes from time.
But Suarez promptly sealed his hat-trick and a vital three points with another fine finish from Neymar's pass to celebrate a year since he made his Barca debut.
"You celebrate wins like this in a different way. It is special because I made my debut a year ago," Suarez told Canal Plus.
"We went behind again, which complicated the game and it is something we have to start looking at."
There was a moment of reflection before kick-off as the Barcelona players entered the field wearing orange t-shirts to honour legendary former Barca player and coach Johan Cruyff, who was diagnosed with lung cancer this week.
And the Camp Nou was stunned early on as Barca conceded first for the eighth time this season when on-loan Atletico Madrid striker Baston swept home his sixth goal of the campaign after Claudio Bravo had blocked Keko's initial attempt.
Barca youngster Sandro Ramirez has struggled with the unenviable task of standing in for Messi during the four-time World Player of the Year's absence.
However, the 20-year-old had a major role to play in a controversial equaliser 11 minutes later as he brilliantly volleyed Sergio Busquets's ball over the top back across goal for Suarez to power home a header from close range.
Yet, replays showed the winger had been in an offside position when he latched onto Busquets's pass.
Suarez was just as ruthless three minutes after the break when Neymar weaved past two defenders and squared for the former Liverpool man to thump his second goal of the evening into the bottom corner.
Mascherano could be in major trouble as his straight red may lead to a four-game ban that would see him miss the clash with Real Madrid on November 21.
However, Suarez ensured Barca weren't to lose any ground on Real in the meantime with a brilliant finish after controlling Neymar's pass on his chest two minutes later.
At the Vicente Calderon, Atletico produced arguably their best display of the season to see of an underwhelming Valencia to keep themselves in touch with the big two.
Martinez took advantage of some atrocious defending from the visitors to slot home his second goal in as many games just after the half hour mark.
Carrasco had far more to do when he doubled the advantage nine minutes later with a brilliant solo run from the halfway line before arrowing a low drive into the bottom corner.
Atletico should have been out of sight at the break as Martinez also had a one-on-one saved by Jaume Domenech and Diego Godin's powerful header was cleared off the line by Jose Luis Gaya.
However, the hosts had to endure a nervy finish when Godin stupdily upended Shkodran Mustafi inside the area 18 minutes from time and Paco Alcacer converted from the spot.
Real Sociedad eased the pressure on former Manchester United manager David Moyes as the Basques thrashed Levante 4-0 on Sunday to move three points clear of the relegation zone.
Former Arsenal forward Carlos Vela opened and rounded off the scoring either side of goals from Imanol Agirretxe and Asier Illaramendi.
Villarreal's dip in form continued as their winless run stretched to three games in a disappointing 0-0 draw at Las Palmas.