We are back underway now after a PA announcement inside Camp Nou asking supporters to refrain from using whistles in the stands - to not confuse the players.

Not something you see often during a football game but normal services have resumed now.

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There is a slight delay here and we don't know what it's for.

Referee Adrian Cordero Vega has gone to the Barcelona dugout to explain it to the home side's bench.

Pau Cubarsi sees the yellow card now as he slides into Rayo Vallecano striker Isi Palazon.

You can feel a touch of impatience building around Camp Nou now.

With 20 minutes to go and only a single goal separating the sides, there’s a growing frustration in the stands and on the pitch.

Barcelona need another to settle this and keep their lead at the top of La Liga table intact.

Or they know Real Madrid will be more than willing to capitalise.

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Pathe Ciss is now cautioned by Adrian Cordero Vega for another foul on Lamine Yamal.

And Barcelona have another free-kick in a dangerous area.

But once again, nothing comes out of Raphinha's set-piece delivery before Dani Olmo fires wide from distance.

Barcelona look rattled at the moment.

But a foul on Lamine Yamal and the another on Pedri gives them some time to regroup.

Rayo Vallecano's Fran Perez is shown the yellow card for the second of the fouls.

Two brilliant saves from Joan Garcia in as may minutes to preserve Barcelona's slender lead.

He produces an acrobatic save to deny Alvaro Garcia's venomous strike first.

Then, a header from substitute Unai Lopez out of Rayo Vallecano's second straight corner needs a reflex save from the Barca custodian.

Barcelona also make a double change now.

Fermin Lopez receives a warm applause from the Camp Nou crowd as he is replaced by Dani Olmo.

Marc Casado also comes on for the Blaugrana as he takes the place of Marc Bernal.

Two more changes from Rayo Vallecano in this game.

Pedro Diaz and Gerard Gumbau is taken off by Inigo Perez as Unai Lopez and Jorge de Frutos is introduced.

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Substitute Ferran Torres is the latest to fire across the goal for Barcelona.

Raphinha looks to get onto the end of it but he doesn't connect despite a valiant slide at the far post.

A spark of brilliance from Lamine Yamal as he gets around the Rayo Vallecano defender and make his way into the box.

But the Barcelona attacker's shot across the goal sails harmlessly wide.

We haven't seen much of the 18-year-old but that was a reminder that he only needs a moment to change a game.

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Ferran Torres is not happy with Barcelona's medical staff as Fermin Lopez is on the floor and awaits their attention.

But it looks like it's nothing serious. The Barcelona attacking midfielder is right back on the field after a very brief spell on the touchline.

Barcelona knock the ball around with confidence at the start of this second half on a sunny afternoon at Camp Nou.

Rayo Vallecano are chasing shadows at the moment as they struggle to get any possession.

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Barcelona make a bright start to the second half.

They win a corner and Fermin Lopez's shot from the edge of the box is blocked in front of the goal by a Rayo Vallecano defender.

However, the referee stops the play for a foul inside the box and the visitors can breath a sigh of relief.

We are back under way for the second half.

Still everything to play for at Camp Nou with hosts Barcelona leading 1-0.

And we have the confirmation of Barcelona's half-time change.

Ferran Torres is replacing Robert Lewandowski for the second.

Meanwhile, we are still waiting for the Rayo Vallecano players to take their places.

The visitors make two changes as Oscar Valentin and Carlos Martin are replaced by Alvaro Garcia and Pacha Espino.

We are moments away from the start of the second half.

The Barcelona players have made their way to the tunnel and Ferran Torres looks set to come on.

Is Robert Lewandowski's involvement in this game over by half-time?

Robert Lewandowski attempted just five passes in the first half.

The 37-year-old also had just 10 touches in the 45 minutes and is yet to attempt a shot in this game.

The Barcelona striker will be hoping for far better service after the break after being starved of involvement so far.

Barcelona:

• Shots - 9
• Shots on target - 4
• Possession - 65%
• xG -1.06

Rayo Vallecano:

• Shots - 2
• Shots on target - 1
• Possession - 35%
• xG - 1.00

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Barcelona have a record of W17, D1, L1 when scoring the opening goal in La Liga this season.

At Camp Nou, they have a record of W11, D0, L0 when scoring the opener this season.

Hansi Flick's side have now scored 36 first-half goals in 29 games this campaign - more than any other team in the Spanish top flight.