In-form Real Madrid reclaimed second spot from Barcelona thanks to a crushing 3-0 win over struggling Villarreal, while Valencia climbed above Sevilla into fourth after Jordi Alba struck an 82nd-minute winner in a 1-0 victory at Real Zaragoza.
Six straight wins had lifted unbeaten Levante, whose annual budget of around 20 million euros is one of the smallest in the league, above Barca and Real to the top of the standings for the first time in the 102-year history of the tiny Valencia-based club.
Their latest success, the first time any club other than Barca and Real have won seven in a row since 2002, gives them 23 points from nine matches, one more than Real and two ahead of Barca following the champions' 1-0 win at Granada on Tuesday.
"This run we are on is almost impossible," Levante coach Juan Ignacio Martinez, who revealed this week that he used to be a bodyguard for a Spanish singer, said at a news conference.
"Having to talk so much about being top of the table is quite difficult psychologically so coming back to win tonight is even more impressive," added the 47-year-old, who is in his debut top-flight campaign.
Daniel Estrada put San Sebastian-based Sociedad ahead in the fourth minute at Levante's Ciutat de Valencia stadium.
Jose Mourinho's Real, who crashed to a shock 1-0 defeat at Levante last month, turned in another impressive performance at their Bernabeu stadium for their fifth win in a row, a run in which they have netted 21 goals.
Karim Benzema starred for Real, netting a sixth-minute opener and sending Angel di Maria clear for the home side's third just after the half hour. Brazilian playmaker Kaka scored the second with a fine strike from just outside the penalty area in the 11th minute.
In Wednesday's other games, 10-man Malaga lost 2-0 at Rayo Vallecano and stay sixth, Getafe drew 2-2 at home to Osasuna and Real Mallorca surrendered the lead to lose 2-1 against visiting Sporting Gijon.
