Lionel Messi broke Pele's all-time scoring milestone for their clubs by netting his 644th career goal for Barcelona, while Atlético Madrid beat Real Sociedad 2-0 to increase its lead of the Spanish league.
Messi, who helped Barcelona win 3-0 at Valladolid, had equaled Pelé's all-time scoring tally on Saturday. His 643rd career goal for Barcelona since his 2004 debut matched Pelé's tally for Santos from 1957-74.
In a meeting between the front-runner and the sensation of the league this season, Atlético put on another dominant performance to show why it is the early title favourite.
Diego Simeone's team took full advantage of its best scoring opportunities and its defense remained airtight from start to finish.
Mario Hermoso headed in a free kick by Yannick Carrasco to put the visitors at San Sebastián ahead four minutes after halftime. Marcos Llorente put the result beyond doubt in the 74th with a powerful strike from the edge of the area.
Atletico moved three points clear of second-place Real Madrid. Sociedad was left in third place at six points adrift. The Basque Country club had led the league earlier this season but has now gone six rounds without a victory.
Barcelona stayed in fifth place at eight points behind Atletico.
Atletico has one more game to play than both Madrid and Barcelona and three more games to play than Sociedad.
Messi scored his team's final goal at Valladolid as Barcelona excelled in an experimental lineup by coach Ronald Koeman.
Koeman has tried several different lineups since he took over Barcelona last summer with the mission to fix a team that had hit rock bottom in a historic 8-2 loss to Bayern Munich.
After seeing his side not win away from home in four games, Koeman opted for his most profound makeover at Valladolid. He deployed a defense of three center backs and kept Antoine Griezmann and Philippe Coutinho - the club's star signings in recent seasons - and midfield leader Sergio Busquets on the bench.
That left Martin Braithwaite alone to spear the attack behind two playmakers in Messi and 18-year-old Pedro "Pedri" González. The scheme also allowed Sergiño Dest to attack deeper on the right flank.
Messi lobbed a pass forward for Clement Lenglet to head in for the 21st-minute opener. Messi then played the ball wide to Dest, who squared it low for Braithwaite to tap home in the 35th.
The connection between Pedri and Messi clicked throughout, but it shone in the 65th when the teenager set up the veteran.
After receiving the ball near the edge of the area, Pedri assisted Messi by deftly rolling his boot over the ball to push it behind him to meet the Argentine's run. The slick pass left Messi clear to finally beat goalie Jordi Masip, who had denied with twice.
Messi also hit the post in stoppage time.
Atletico was without João Félix due to a throat infection. It made up for the absence of its most dynamic forward by applying a suffocating defense to nullify Sociedad's normally fluid attack.
Sociedad had David Silva back after he recovered from a muscle injury that had sidelined him for three consecutive matches.
Silva's return was not enough, however, to break through the visitors' defensive block that left Jan Oblak with very little work. The Slovenian goalkeeper didn't have to make a save until the 83rd when he stretched to parry a free kick by Martín Merquelanz.
Oblak has conceded only five goals in 13 league games.
Hermoso had struggled to break into Atlético's starting 11 last season, but he has earned a spot on the left side of the three-man defense Simeone has used at times this campaign. The goal was his second of the season.
After Hermoso's opener, Atlético pushed for a second goal with Carrasco twice threatening with his crosses from the left flank. Another attack down the left led to Luis Suárez receiving the ball deep in the box. His pass intended for Carrasco was deflected by a defender into the path of Llorente, who blasted it home.
Villarreal held onto fourth place despite a 1-1 draw with Athletic Bilbao.
A late strike from long distance by Jesús "Suso" Fernández gave Sevilla a 1-0 win at Valencia.
Osasuna stayed in last place after twice giving up leads in a 2-2 draw at Elche.
Huesca likewise stayed in the relegation zone after a 1-1 draw with Levante.