Long-standing tennis world number one Serena Williams is convinced that she would have been punished much more severely if she had freaked out like Olympic champion Alexander Zverev.

“There is absolutely a double standard.

I probably would have gone to jail if I did that.

For real.

No joke," said the 23-time Grand Slam winner in a CNN interview.

"I am who I am - on and off the pitch, and I'm also very passionate, but there are definitely different standards."

Zverev (24) recently hit the referee's chair with his racket several times at the tournament in Acapulco, Mexico, after a defeat in doubles, on which the referee was still sitting.

He was disqualified and fined $40,000.

In addition, the Hamburger has to pay back the prize money of more than 30,000 dollars and loses the points for the world rankings.

There should also be a further investigation.

Zverev wins, Struff fails

Williams (40) also had outbursts of anger from time to time in her exceptional career.

She was even on probation, as she recalled in the interview of an incident more than twelve years old.

During her semifinals at the 2009 US Open against eventual winner Kim Clijsters, Williams verbally attacked a linesman who ruled a faulty serve on a serve.

She received a two-year suspended sentence and a $175,000 fine.

In 2018 in Flushing Meadows she presented herself as a bad loser in the final against Naomi Osaka and constantly insulted the referee.

"At the end of the day, I am who I am and I love who I am," she said.

Meanwhile, the German Davis Cup team has to worry about entering the group phase.

In the first round duel in Brazil it is only 1:1 after the first day.

Zverev lived up to his role as favorite against Brazilian Thiago Seyboth Wild on Friday with a clear 6: 4, 6: 2 in the opening singles.

After that, Jan-Lennard Struff made a mistake against the Brazilian number one Thiago Monteiro and had to admit defeat 3: 6, 6: 1, 3: 6.

This Saturday, starting at 6:00 p.m. CET (Sportdeutschland.tv), the doubles match with Kevin Krawietz and Tim Pütz is on the agenda.

This is followed by two more singles.

First, Zverev plays against Monteiro in the top singles, then Struff meets Seyboth Wild.

Changes are still possible until shortly before the games.

In the event of a win, Germany would qualify for the group stage in September.

A week and a half after his disqualification at the ATP tournament in Acapulco, Zverev had a solid performance against number 216 in the world to achieve the expected success.

The German number one managed a quick break in the first set, after 51 minutes he got the first round with the second set ball.

The third in the world rankings had no problems with the 21-year-old outsider in the second set either.

Zverev twice took the serve from the Brazilian, who had his hand treated briefly in the middle of the sentence, and made the safe success in the first attempt perfect.

"I think it was a solid match for me," said Zverev after his undisputed victory.

“Now Jan-Lennard can go into the second individual with a little more calm.

The pressure is on the Brazilians now.”

But Struff could not use the good starting position.

Spurred on by the clamoring Brazilian fans, Monteiro put in a strong performance and clinched the first half after 37 minutes.

After that, Struff increased and quickly equalized the set.

But then he conceded an early break in the deciding set and had to admit defeat to number 114 in the world.

After freaking out in Acapulco, Zverev only decided at short notice to make his comeback in the Davis Cup.

Actually, he had already canceled the game because it didn't fit into his tournament schedule due to the Masters 1000 tournament in Indian Wells taking place next week.

But after the negative headlines following his behavior in Acapulco, Zverev is also concerned with polishing his image again.

With the clear opening success against Wild, he took at least a small step towards improving his image.

On Saturday it will be up to the German number one again if Germany doesn't lose Boris Becker in Brazil like they did 30 years ago.