The German Football Federation (DFB) has condemned the sexist remarks made on social media about Union Berlin coach Marie-Louise Eta.

"The comments are unacceptable. They're not directed solely at a single individual, but call into question values that are central to our sport: respect, fairness, and equality," DFB vice-president Celia Sasic, told the t-online news portal on Sunday.

Eta became the first woman to be the head coach of a men's team in one of the top leagues in Europe. She made her debut on Saturday with a 2-1 defeat to VfL Wolfsburg.

She kept receiving hate comments on social media after the match and the club directly responded to some of them, which Sasic said was "absolutely the right thing."

The DFB is also prepared to deal with hate messages directed at Eta during matches. Sasic explained that the federation has clear procedures in place to filter out, report, and, if necessary, forward offensive or criminal comments to the public prosecutor's office.

"As a general rule, the DFB monitors every match very closely when it comes to discrimination or inappropriate behaviour. There is zero tolerance for sexist or discriminatory incidents," she said.

Eta herself said that the comments don't bother her.

"It says more about the people posting it online than about the people being talked about," she said.

It seemed as if the entire football world had their eyes on the Bundesliga on Saturday to witness Marie-Louise Eta's historic debut as head coach of Union Berlin.

The Spanish newspaper AS published a video showin Eta's arrival on the pitch as the first women to coach a men's team in one of Europe's top leagues.

Even the Argentinian sports newspaper Olé briefly featured Eta on the home page of its news portal, pushing out the preview of the Superclásico between Boca Juniors and River Plate.

"Revolution in the Bundesliga: Marie-Louise Eta makes debut as Union Berlin coach," Olé wrote. "A historic day for German football."

The Spanish newspaper Marca said: "The anticipation was immense, and a deafening roar of jubilation shook the picturesque Stadion An der Alten Försterei when Marie-Louise Eta emerged from the tunnel. Every photographer's lens was pointed at her. And that was no wonder, because they were witnessing a historic moment."

Eta was closely followed by the a swarm of photographers when she hurried to one side of the pitch for an interview with broadcasters DAZN. And they moved along with her when she crossed the pitch again to talk to Sky TV.

"She was the centre of attention. A real revolution," Olé said.

Eta, however, stressed: "It's not about me, it's about football."

Her debut wasn't all about celebrations as Union lost 2-1 to VfL Wolfsburg and extended their winless run to four games.