* Sanchez scores twice in 4-1 victory
* Ronaldo grabs late winner at Levante
Alexis Sanchez struck twice and created a goal for Neymar as Barcelona recovered from conceding early to maintain their perfect La Liga start with a 4-1 win at home to Real Valladolid on Saturday.
An eighth victory in eight games for the champions restored their five-point advantage over arch-rivals Real Madrid who needed a Cristiano Ronaldo goal in the fourth minute of stoppage time to secure a 3-2 triumph at Levante earlier.
Atletico Madrid, the only other team with seven wins from their opening seven matches, can join Barca on 24 points at the top of the table with a win at home to Celta Vigo on Sunday (1000 GMT).
Valladolid forward Javi Guerra silenced the Nou Camp when he headed in a corner in the 10th minute but Barca were level four minutes later, Alexis lashing the ball home from just outside the penalty area.
Cristian Tello squared for Xavi to sidefoot the ball in seven minutes after the break before Neymar sent Alexis clear on the right in the 64th minute and he sent a precise shot into the far corner.
The Chilean returned the compliment by setting up Brazil forward Neymar to make it 4-1 six minutes later as Barca, who have also won both Champions League outings this season, continued their impressive form under new coach Gerardo Martino.
The Argentine is the first coach to win his opening eight matches in La Liga while Barca are the first team to start a campaign with eight victories since Real in the late 1980s.
"You play 10 good games, one average one and one bad one and people, the media, criticise you," Alexis told Gol TV.
"But this victory will help me and the team," added the striker who has not always convinced since joining Barca from Udinese in 2011.
"Barca are always obliged to win and by a wide margin."
Real are flying in Europe after resounding Champions League victories over Galatasaray and FC Copenhagen but turned in another disappointing domestic performance at Levante following last weekend's 1-0 defeat at home to Atletico.
They twice had to come from behind at Levante's Ciutat de Valencia stadium before Ronaldo rifled a 94th-minute shot from the corner of the area and it glanced off a defender before deflecting into the net off a post.
It was desperately hard on a plucky Levante side and their fans but moved Real back above Villarreal, who won 3-0 at home to Granada on Friday, into third place on 19 points.
"The first half was not good but the second turned out differently," Real coach Carlo Ancelotti told a news conference.
"We need more concentration because we gifted two goals," added the Italian. "The team dug deep at the end and never gave up. When our team plays, five minutes is all it takes to win a game."
Levante, whose entire squad is worth just over a third of the record 100 million euros ($136 million) Real paid for Wales winger Gareth Bale in the close season, took the lead in the 57th minute when Papa Babacar Diawara finished off a superb counter attack.
The goal appeared to wake Real, missing the injured Bale, from their lethargy and Sergio Ramos levelled four minutes later when he volleyed home an Angel Di Maria corner.
Levante rallied and substitute Nabil El Zhar fired through a crowd of defenders into the net in the 86th minute to put the home side within touching distance of an unlikely victory.
There was still time for plenty more drama and Real substitute Alvaro Morata levelled when he blasted the ball in from close range in the 90th minute.
Ronaldo, who ripped off his shirt after scoring the winner, now has seven goals in the league this season.
The Portugal forward is one behind Barca's World Player of the Year Lionel Messi, who is sidelined with a hamstring strain, and Atletico forward Diego Costa.
($1 = 0.7355 euros)