Real's Eder Militao clips the heel of Gavi and that gives Barcelona a free-kick to get the ball into the Real penalty area for the first time.

Ex-Chelsea man Marcos Alonso swings it in from deep but the home side deal with it comfortably and clear their lines.

Real Madrid get a corner from the left and Luka Modric's low delivery is sent behind and he gets another go.

This time he's looking for the back post but Marc-Andre ter Stegen in the Barcelona goal does well to not only get a punch on the ball, but also send it miles away from goal when under pressure. Solid goalkeeping.

You can now see why Xavi was saying Real Madrid were favourites. Barca haven't got started yet.

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The ball is in the net but Karim Benzema is offside. It's a shame as it's a lovely finish.

Vinicius Jr chipped a ball to the back post, Benzema took a touch on the chest and then, while falling over, shot on the volley past Marc-Andre ter Stegen.

But, luckily for Barcelona, Benzema was offside when the ball was played to him. Great technique, but no goal.

Barcelona defender Jules Kounde just about gets there with an important header as Karim Benzema was winding up something special from the edge of the penalty area.

The always exciting Vinicius Jr picks up the ball down the left wing as the noise levels instantly increase at the Bernabeu.

A step over and go sees him sprint past Frenkie de Jong, but that has left him at a tight angle and he can't test Marc-Andre ter Stegen with the shot.

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It has been a very bright start from the hosts, with Barcelona struggling to get possession. Ronald Araujo clatters into Vinicius Jr with an early reducer and is lucky to not see yellow.

Luka Modric may well be 37 but he still has the legs for a lung-busting run from the halfway line.

He chases on to a through ball and only some excellent tracking back from Jules Kounde forces Modric to shoot only into the side netting.

Almost a disastrous start for Barcelona's completely rehashed back four.

Right, with the Copa del Rey semi-final 1st leg starting, let's get a flavour of the room here.

Which of these sides are going to reach the final after the two legs have finished? Thumbs up for Real Madrid (as they are at home today) and thumbs down for Barcelona.

Go...

The players are out at the Bernabeu, the pre-game pleasantries have been done and we are ready for the latest El Clasico.

Karim Benzema has scored 13 goals in 40 El Clasico appearances and can reach Francisco Gento (14 goals in 42 games) and Ferenc Puskas (14 goals in 18) as Real Madrid's joint-fourth top scorer in history of this duel.

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Real Madrid have been eliminated in three of their last four two-leg knockout ties versus Barcelona in Copa del Rey.

They were successful in the semi-finals in 2013 (drawing 1-1 at home and winning 3-1 at the Nou Camp.

As Real Madrid welcome Barcelona to the Bernabeu this evening, Carlo Ancelotti looks to take advantage of the first leg home tie.

He said: "We have to show personality and courage to deliver a complete performance. When this team gets close to a trophy, they really up the temperature.

"As always, we're looking forward to this game, it's always nice. We're not far away from playing a final."

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This stat shows how important Robert Lewandowski, La Liga's top goalscorer with 15 goals this season but missing tonight, has been to Barcelona.

He has attempted 22% of Barcelona's shots in La Liga this season (75/347), with only Getafe's Enes Unal (25% - 52/211) and Mallorca's Vedat Muriqi (24% - 50/209) having a higher percentage of his team's shots in the competition.

Both teams come into tonight's match after slipping up in their league matches at the weekend.

Barcelona missed the chance to extend their lead at the top of La Liga after suffering an unexpected 1-0 defeat at relegation-battling Almeria.

That came a day after Real Madrid’s own title hopes looked to have suffered a blow after they played out a 1-1 draw at home to 10-man rivals Atletico Madrid on Saturday.

However, Barca, knocked out of the Europa League by Manchester United last Thursday, fell behind against Almeria to a first-half goal from El Bilal Toure and could not find a way back as they suffered only their second league defeat of the season.

Despite the loss though, the Catalan giants remain seven points clear of Real at the top of the table.

Andy West
Spanish football writer

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Barcelona are sitting pretty at the top of La Liga, holding a seven-point lead over Real Madrid after just two league defeats, and have already claimed the first silverware of the season by convincingly beating their arch-rivals 3-1 in January's Super Cup.

But they have also been eliminated from Europe - twice - and hit a bad run of form, with their attacking problems starkly shown by Sunday's turgid 1-0 loss at lowly Almeria.

Heading into the Copa del Rey semi-final first leg against Real at the Bernabeu, those contradictions neatly summarise Barca's current state: plenty of promise, but worrying signs that everything could quickly unravel.

Similarly, the delicate balance between positives and negatives reflects the work of manager Xavi, who is being forced to make tactical compromises to satisfy short-term demands for success.

Xavi, without doubt, has made Barca better since he was appointed in November 2021. He inherited a mess, with a lack of direction on the field and the aftermath of a financial disaster behind the scenes.

• Read more of Andy's feature by clicking here

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In the most recent El Clasico Carlo Ancelotti's men were on the end of a 3-1 beating in the Spanish Super Cup final.

"We have assessed everything," said the Italian. "In the Supercopa, we lacked commitment and decisiveness, with individual mistakes that won't be repeated.

"We are close to winning an important competition and we are going to compete. It's not the decisive match, but we want to take advantage."

As always feel free to have your say on all of tonight's action. Send us a message on Twitter using #bbcfootball to get involved.

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Sergio Busquets will make his 46th appearance in El Clasico in all competitions tonight, surpassing Lionel Messi and Sergio Ramos (45 each) as the player with the most appearances in the games.

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This is a cup match tonight but this is how it stands in La Liga and it's set up nicely for a great title showdown.

In between the two legs of this Copa del Rey semi-final Barcelona entertain Real Madrid in La Liga on Sunday, 19 March, before the second leg at the Nou Camp on Wednesday, 5 April.

In the other semi-final, Osasuna hold an advantage after their 1-0 home win against Athletic Bilbao in the first leg on Wednesday, with the second leg set for 4 April.

The final will be held in Seville on 6 May and if either Osasuna or Athletic lift the trophy it will see them qualify for next season's Europa League.

Barring an almighty league collapse, Barcelona and Real Madrid will qualify for next season's Champions League spots via their La Liga positions.