On Saturday night the Spanish season opens with ‘el clásico’ but this time it is different. At 6pm at the Estadi Johan Cruyff, for the first time ever, FC Barcelona Femení will play Real Madrid – even if they are not actually called that yet. By popular demand Madrid have finally joined the women’s professional game and they make their debut in Catalonia against the team set to be their great adversaries, last season’s league and Champions League runners-up. Tickets are on sale from €5 and they anticipate a full house for a historic rivalry with an entire history still to be written, starting right there.

Officially Barcelona face Club Deportivo Tacón but their opponents will play in white; they have been preparing for this match – their first in the first division – at Real Madrid’s Valdebebas training ground, where they will also play their home games; they made galáctico signings over the summer; and they have been integrated into the structure at the Santiago Bernabéu. Soon, they will change their name too: next season, CD Tacón will be known as what they have become: Real Madrid’s women’s team.

Madrid announced a €400,000 deal to take over Tacón in June, although the move has to be ratified by the club’s assembly this month. Madrid had been under pressure to found a women’s team for some time and, while there were doubts about the best way to do so, Tacón’s promotion to the first division was an opportunity to finalise an agreement that they had been working on for some time.

Tacón’s name comes from the words trabajo (work), atrevimiento (daring/bravery), conocimiento (knowledge), organización (organisation) and notoriedad (notoriety) and spells out high heel – the logo of the club until Real Madrid’s replaces it. The club’s president, Ana Rosell, is a former player at Atlético Madrid but was both a socio (member) and a compromisario at Real Madrid – one of those chosen members with a voice and vote at the club’s assemblies. The vice-president is Sergio Ramos’s brother, René.

Tacón initially began with girls’ youth teams in 2014 but merged with Canillas, a team from the north-east of the city, in 2016. That allowed for a senior team. Rossell had first proposed collaboration with Real Madrid three years ago.

Former Real Madrid player Roberto Carlos (bottom row, right) and current Real Madrid players and staff watch Tacón’s friendly against Sevilla. Photograph: Cordon Press/Cordon Press/Alamy Live News

Madrid were also in discussions with Madrid Club de Fútbol Femenina, founded by Alfredo Ulloa, who said he had set the club up because his daughter could not play at Madrid where there were no girls’ teams. Ulloa said he was not sure about “selling” the club to Real Madrid; he would have preferred to collaborate with them.

Rosell will continue to run Tacón/Real Madrid following the €400,000 deal and the new team is expected to have a budget of around €2m – more than any side in Spain other than FC Barcelona. This summer they signed the US-English striker Chioma Ubogagu, Swedish internationals Kosovare Asllani and Sofia Jakobsson, and the Brazilian international Thaisa.

Twenty-one per cent of Real Madrid’s socios are women and demands for them to have a women’s team go back five years. Barcelona’s women’s team was founded in 1998, Atlético’s in 2001 and Athletic Club Bilbao’s in 2002. The club was unsure of the best way to found the side: president Florentino Pérez had said he favoured building a team from scratch, starting at youth level, yet he had also said on other occasions that there was little point in having a women’s team unless it was built to “win”. That idea has prevailed with the move to bring Tacón on board following their promotion and the subsequent signings.

Kosovare Asllani, one of Tacón’s summer signings, in action. Photograph: Cordon Press/Alamy Live News

If there could be some unease at the appropriation of a women’s team, it is a process that has been followed before – Atlético and Barcelona built their own sides, but Betis, Sevilla, Deportivo and Valencia all merged with existing clubs – and these moves were widely welcomed as raising the profile of the women’s game, which has grown enormously in recent years.

On the day the deal was announced, the sports daily Marca led on a photoshopped image depicting Real Madrid women’s players celebrating a goal in the club’s kit. “Women’s football goes into another dimension,” the headline said.

Some criticised that headline. After all, it had already come a long way and there had been other breakthroughs. Spain’s women had only narrowly been knocked out by the world champions USA in the World Cup, which was a big TV success this summer; Barcelona, who had the England striker Toni Duggan among their ranks, had reached the Champions League final; and a match between Atlético and Barcelona had attracted 60,738 to the Wanda Metropolitano. And yet few doubted that it was true: this was a significant step.

Barcelona’s players celebrate a goal during last season’s match against Atlético Madrid at the Wanda Metropolitano in Madrid. Photograph: Kiko Huesca/EPA-EFE

“Madrid is a monster that we were missing in women’s football, so we are all celebrating this,” said Rafa de Amo, the president of the women’s football committee at the Federation.

“We all wanted this: it will be nice to see the battles between Barcelona, Atlético and Real Madrid. It’s a great club and they’ll bet heavily on women’s football,” the Barcelona player Andrea Pereira said. Her teammate, the Spain international Mapi León, insisted: “It is good for women’s football to have Real Madrid there.”

“They’re a club with a lot of ‘pull’,” the Atlético captain, Amanda Sampedro, joked. “It’s good to have them but only if we can beat them; if not, don’t come.”