The 19-year-old struggled in Barca's first match of the season at Elche but improved against Athletic Club in the second, albeit without finding the net.

Flick said the Spanish World Cup winner is returning to his best, which Lamine has not hit since suffering a hamstring injury in April.

The winger returned at the World Cup but, despite Spain's success, had limited individual impact at the tournament.

"I know everyone is worried about how Lamine is, how he is doing. And of course, look at his situation, he played a World Cup after a huge injury," Flick told reporters Sunday.

"Now he's coming back after three weeks' holiday... and also the first game maybe was not his best game.

"But I said this, I was very happy that he started the game and he worked for the team."

Lamine disappointed in the first half against Athletic on Thursday but stepped up a gear after the break.

"He played 90 minutes against Bilbao. And for him at the moment, it's also good to (have) 90 minutes on the pitch," continued Flick.

"We saw him in some situations really on this top level. And now, you couldn't see this in the training (session) today, but I saw it, and it was excellent.

"Everyone loves Lamine, and he's in a good way. And we have to support him, and we do that."

Lamine seemed in a bad mood after the game against Elche but happier in training ahead of the Rayo clash.

"Of course, it's always good when the players are smiling, but it's not every day the same day," added Flick. "I'm also not smiling every day - it's like that."

Barca won both of their opening fixtures with Raphinha playing as a makeshift number nine, with the champions unable to land top target Julian Alvarez from Atletico Madrid.

"Of course I'm happy with my team, (sporting director) Deco is working on that to strengthen the team. We don't have pressure," said Flick, reiterating he is content with the players available to him if Barca don't sign a new striker.