Barcelona extended their near-perfect start thanks to another Lionel Messi double but again suffered the defensive lapses that have plagued them this season in a nervy 4-2 La Liga win at Real Mallorca.
Atletico Madrid kept pace with the leaders three points back in second with a 2-0 success at home to Getafe, while third-placed Real Madrid were indebted to goals from a wounded Cristiano Ronaldo and substitute Alvaro Morata in a 2-1 win in almost unplayable conditions at waterlogged Levante.
Deployed at centre forward in the absence of injured strikers Karim Benzema and Gonzalo Higuain, Ronaldo sustained a nasty cut above his left eye when he was caught by David Navarro's elbow in the opening minutes of the match in Valencia.
After having it taped up on the side of the pitch, he popped up at the far post in the 21st minute, controlled a looping ball on his thigh and crashed a superb volley high into the net.
The Portuguese was replaced at halftime by centre back Raul Albiol as a precaution and Levante substitute Angel Luis Rodriguez levelled in the 62nd minute before Xabi Alonso had a penalty saved by home goalkeeper Gustavo Munua.
An unmarked Morata nodded in Alonso's inswinging free kick six minutes from time moments after entering the fray and Jose Mourinho's side stayed five points behind Atletico, whom they host on Dec. 1.
Unbeaten Barca's 10th victory in 11 La Liga matches, in which Xavi and Cristian Tello also scored, and haul of 31 points equalled the best start to a league campaign achieved twice by Real - in the 1968-69 and 1991-92 seasons.
However, Barca coach Tito Vilanova will be wondering how inept defending allowed Mallorca to score twice early in the second half to get back to 3-2 before Messi struck his second of the night with 20 minutes left.
It was the World Player of the Year's 76th goal of 2012 for club and country - 64 for Barca and 12 for Argentina - and he is closing in on the record for a calendar year of 85 set by German Gerd Mueller in 1972.
The 25-year-old has 15 in La Liga this season, three ahead of Ronaldo.
"The team is in a situation right now when any little mistake costs you a goal," Vilanova told a news conference.
"Maybe one goal against would have been a just reflection of how the match went but not two," added Pep Guardiola's former assistant, who stepped up to take the top job at the end of last season when Guardiola quit.
Barca, whose only dropped points came in October's 2-2 draw at home to champions Real, took a 28th-minute lead at Mallorca's Iberostar stadium when Xavi left goalkeeper Dudu Aouate rooted to the spot with a sumptuous free kick.
Messi, who had his new-born son's name Thiago written on his boots, made it 2-0 when Aouate let his low drive squirm past him in the 44th minute and Tello cut in from the left and curled into the far corner a minute later.
Mallorca kept plugging away and were rewarded 10 minutes into the second period when Javier Mascherano surrendered possession on the right and the ball eventually fell to Michael Pereira who smashed it past Victor Valdes.
Victor Casadesus scored from the spot two minutes later after a Sergio Busquets handball in the penalty area and the home fans sniffed an unlikely comeback.
However, substitute Alexis Sanchez chested down a Daniel Alves centre for Messi and he took a touch before sending a blistering shot into the roof of the net.
"It's not that we felt the win was in danger but I think the incident that led to the second goal was bad luck," central defender Gerard Pique, making his first start after a two-month injury layoff, said in an interview with Spanish television.
"We were tense towards the end because another similar passage of play could have brought them level," he added.
"In general we played well and we were superior although in the opening 15 minutes of the second half we suffered a bit."
Valencia's poor away form continued when Aly Cissokho scored and was later sent off after conceding a penalty in a 1-1 draw at Real Valladolid.
Valencia had drawn one and lost four of their five away games this season and they had to hang on for the final half hour with 10 men at Valladolid's Jose Zorrilla stadium after Cissokho was shown a straight red in the 64th minute.
The French fullback, who nodded his side ahead in the 14th minute, felled Julian Omar in the area and Victor Perez stroked the spot kick past Diego Alves to make it 1-1.
Valencia have 15 points in ninth, ahead of Valladolid thanks to a superior goal difference.
Athletic Bilbao also ended their match with 10 men but repelled intense late pressure to secure a 2-1 home win over Sevilla, only a fourth victory of the campaign that lifted the Basque club to 12th on 14 points.