A late goal by new signing Dani Olmo gave Barcelona a nervy 2-1 comeback victory at Rayo Vallecano on Tuesday, as the LaLiga leaders continued their perfect start to the season with a third consecutive win.

After missing Barca's first two games as he was unregistered due the club's struggles to comply with LaLiga's Financial Fair Play (FFP) rules, Olmo came off the bench in the second half to give Barca the spark they needed on his debut after signing from RB Leipzig.

He struck the winner in the 82nd minute after Pedri's goal on a counter-attack in the 60th minute had cancelled out Unai Lopez's early opener for Rayo.

The win put Barcelona top the standings on nine points from three games, two ahead second-placed Villarreal. Rayo are eighth on four points.

Vallecas has not been a happy hunting ground for Barcelona in recent years and the Catalan giants have failed to win a league game at the raucous stadium on the outskirts of Madrid since November 2018.

Rayo dominated proceedings in the first half and took the lead from a quick counter started by Jorge de Frutos who set up Lopez to score in the ninth minute.

Alvaro Garcia and Isi Palazon had great chances as Rayo started the game aggressively, pressuring Barca high and bursting forward on counter attacks.

But Barca were livelier after the break, with manager Hansi Flick bringing the versatile Olmo off the bench.

Olmo's electric performances were central to Spain's Euro 2024 triumph and he finished as the tournament's joint top scorer with three goals and was one of six Spain players in UEFA's team of the tournament.

He fired a thunderous strike from long range in the 57th minute that cannoned off the crossbar and was a constant menace for Rayo's defence.

Barca levelled in the 60th minute thanks to a quick counter attack started by Pedri, who passed to Raphinha in the left channel and burst forward to receive the ball back from his team mate before guiding his finish into the bottom right corner.

Barca thought they had scored a second through Robert Lewandowski in the 71st minute, but referee Cesar Soto Grado ruled out his effort due to a foul in the build up that he spotted in a VAR review.

However, Olmo gave Barca a deserved win after a fine combination with Lamine Yamal, who drove to the byline before cutting the ball back for an unmarked Olmo inside the box, who netted a curling strike just inside the far post.