Gavi put Barcelona ahead from close range after 17 minutes and teenage winger Yamal netted the second early after the break.

Barcelona signed Olmo in August for around 55 million euros ($57 million), but with the club unable to meet LaLiga's wage capthe attacking midfielder and Spain international was registered only for the first half of the season.

The future of Olmo and young forward Pau Victor at the Catalan giants has been on hold over a financial and administrative limbo that prevented their registration beyond 2024.

Manager Hansi Flick expressed frustration over Barcelona's struggle to acquire new players' licences for Dani Olmo and Pau Victor but remained optimistic ahead of their Copa del Rey match against Barbastro, praising the duo's attitude.

Barcelona's star winger Lamine Yamal has vowed to "come back better" after injuring his right ankle earlier this month during a La Liga match.

Barca have now gone three games without a LaLiga win having picked up five points out of a possible 21, suffering defeats by Leganes and Las Palmas in their previous two home games. They are three points behind Atletico having played a game more.

Pedri sent the Catalans ahead but second-half goals from Rodrigo De Paul and Alexander Sorloth helped Diego Simeone's side move three points clear at the top of the table, having played one match fewer than Barca.

"Tests carried out this morning revealed a grade 1 injury to a ligament in the ankle," Barcelona said in a statement on Monday.

La Liga leaders Barcelona stumbled 1-0 at home against Leganes on Sunday as they suffered another blow in the Spanish title race.

La Liga leaders Barcelona dropped two points in the title race as Real Betis twice came from behind to snatch a 2-2 draw in an entertaining battle on Saturday.

Barcelona coach Hansi Flick on Friday said teenage winger Lamine Yamal will return after three weeks out with injury for this weekend's game against Las Palmas in La Liga.

The veteran striker slotted home from the spot in the 10th minute to fire the Catalans ahead and reach his milestone, adding a second late on after Dani Olmo's goal to inflict the French side's first defeat.

Raphinha and Robert Lewandowski's goals put the Catalans in a healthy position but Marc Casado's red card in the 82nd minute helped Celta start the fightback to snatch a point.

Lewandowski suffered a back injury in Sunday's 1-0 defeat at Real Sociedad during which he had a goal controversially disallowed.

Lewandowski's early disallowed strike led to furious debate over whether the Polish forward had been offside or not.

Barcelona coach Hansi Flick said he thought playmaker Dani Olmo would be ready despite feeling unwell overnight, while defender Pau Cubarsi can play despite suffering a cut on his face during the team's Champions League win over Red Star Belgrade on Wednesday.

It was another commanding victory for LaLiga leaders Barcelona who are in an imperious vein of form, scoring 24 goals in six successive wins in all competitions, including thrashings of Bayern Munich and Real Madrid.

Dani Olmo struck twice for Barcelona on his first start after an injury absence as they beat local rivals Espanyol 3-1 on Sunday to move nine points clear at the top of La Liga.

"Honestly I don't see it as extraordinary, even if some people do... when I was little I also looked on from the outside, watching from my house seeing Messi lift Ballons d'Or and thinking it was incredible. Once you are on the inside, you take it normally, naturally, although if I stop to think about it, it's something really big."

The Catalan giants triumphed at the Santiago Bernabeu to snap Madrid's run of 42 matches unbeaten and continue their own revival under the German coach who arrived this summer.