Barcelona recovered from their midweek defeat to Paris Saint-Germain as goals from Lionel Messi and Neymar handed them a comfortable 2-0 win away to nine-man Rayo Vallecano on Saturday.
Valencia remained just two points behind the Catalans at the top of the table with a 3-1 win over champions Atletico Madrid thanks to three goals in the opening 13 minutes.
After resisting some early pressure from Rayo, Barcelona killed the game off with two goals in as many minutes just after the half hour mark as Messi and Neymar took advantage of the hosts' high line to continued their fine goalscoring form.
Rayo were reduced to nine men after half-time as Jorge Morcillo and Javier Aquino were shown second yellow cards and Barca saw the game out to preserve their record of not conceding so far this season in La Liga.
Barca now lead third-placed Atletico by five points and Real Madrid by seven, but Real can cut the gap when they face Athletic Bilbao at the Santiago Bernabeu on Sunday.
"When you play on a pitch as small as here, playing with intensity is essential and I think we were up to the task," said Barca boss Luis Enrique.
Claudio Bravo now holds the record for an unbeaten start to a La Liga season and Barca's Chilean goalkeeper needed to be at his best early on to prevent Alberto Bueno firing Rayo into the lead.
However, Enrique dismissed the importance of Bravo's 630-minute run without conceding.
"The only statistics that interest me are at the end of the season that will say whether we have deserved to win the title."
Rayo's offside trap was being breached regularly as the half wore on and moments after Messi had a goal ruled out, the Argentine showed great composure to dink the ball over the advancing Tono to open the scoring.
Barca doubled their advantage a minute later as this time Munir El Hadaddi fed Neymar and the Brazilian took his time before drilling the ball into the far corner.
Rayo could have been back in the game early after the restart had it not been for another fine save from Bravo to deny Leo Baptistao.
- Red cards -
However, any hope for Paco Jemez's men was ended when Morcillo was given his marching orders for an unnecessary lunge from behind on Neymar.
Messi then missed a number of chances to add to his tally in the final quarter, leaving him still just two goals shy of Telmo Zarra's all-time La Liga goals record of 251, before a disappointing afternoon for Rayo was rounded off when Aquino was also sent-off for a late challenge on Sergio Busquets.
Atletico, meanwhile, paid for their efforts in beating Italian champions Juventus in midweek as a Miranda own goal, Andre Gomes's strike and a Nicolas Otamendi header gave Valencia a dream start at Mestalla.
Mario Mandzukic reduced the arrears on the half hour mark, but any hopes of an Atletico comeback were halted when Diego Alves saved Guillherme Siqueira's tame penalty just before half-time and they ended the match with 10 men as substitute Alessio Cerci was sent-off in stoppage time.
"Valencia started very strongly and we made mistakes that we don't usually make," said Atletico boss Diego Simeone.
"After that Atletico played very well and they didn't have any more chances. If we had scored the penalty, perhaps it would have been different."
Valencia coach Nuno Espirito Santo refused to specify what he would deem as success for his side come the end of the season, but believes they can get even better with star summer signing Alvaro Negredo set to return from injury after the upcoming international break.
"Our objective is to keep growing and keep improving as individuals and as a team.
"Today is a great day for us, but I am very optimistic and I think we will improve."