Billie Jean King and Margaret Court are no longer only tennis rivals.

Billie Jean King and Margaret Court were born on different sides of the globe.

King, 74, is from California in the US, and Court, 75, was born one year earlier in Perth, Western Australia.

They differ in upbringing, experiences, perspectives and world views. The only thing that binds them? Tennis.

Both were champion tennis players, connected by a clay court and a yearning to be the best. They competed against each other for grand slam titles in a time when women in sport were fighting to be seen at all.

Court temporarily retired after losing to King during the Wimbledon semi-finals in 1966. Four years later, she was back and beat her rival in the finals for the same title. They retired six years apart and, now, they are once more making headlines. Again as rivals.

King is calling for the Margaret Court Arena in Melbourne to be renamed because of Court’s stance against same-sex marriage.

“She says so many derogatory things about my community,” King said on Saturday, The Sydney Morning Herald reports.

The two-time Australian Open winner who's been in a relationship with her partner, her former doubles partner, Ilana Kloss since 1987, said she would refuse to play at the arena if she was still on circuit.

"I personally don't think she should have her name [on the arena] anymore. If you were talking about Indigenous people, Jews or any other people, I can't imagine the public would want someone to have their name on something."

Though she was married to Larry King in 1964, King soon discovered she was attracted to women. She started a relationship in 1971 with her secretary and publicly acknowledged the relationship for the first time in 1981.

She and her husband remained married throughout - they stayed close even when they did eventually separate, and King is the godmother to her former husband's child. She and Larry finally divorced in 1987 when King fell in love with Kloss. The two have been together ever since.

The push to change the name of Margaret Court Arena first came in May last year after Court vowed to boycott Qantas after the airline's CEO Alan Joyce announced his support of same-sex marriage in the lead up to the nation's vote on the issue.

"I believe in marriage as a union between a man and a woman as stated in the Bible," she wrote in a column for The West Australian at the time.

Speaking to Vision Christian Radio shortly after the article was published, Court, who is also a Christian pastor, implied homosexuals are the victims of childhood sexual abuse, and said Christianity was there to "help gay people overcome", The West Australian reports.

She also shared her views on transgender children: "What confusion to a child," she told the radio station. "I get confused talking about it. You can think, 'I'm a boy', and it affects your emotions and feelings and everything else. That's all the devil."

Now, Court's husband Barry Court has sent a letter to media organisations defending his wife against King's accusations: "Margaret always admired Billie Jean as her number one opponent and often praised her ability."

"I suggest Billie Jean first check her facts before making allegations against my wife," he wrote.

"We have reputable sources review all her press releases and interviews and cannot trace these remarks back to Margaret."

Prime Minister Malcolm Turnbull said in May, 2017, the arena would stay named after Court because "she is one of the greatest of greats of tennis", Australian Financial Review reports.

However, this is the first time a fellow 'great' such as King has weighed in.

King said she was "looking forward" to discussing the issue further with Court at the 2018 Australian Open.

"I was looking forward to seeing her, we usually sit together ... We usually have lunch," King told The Sydney Morning Herald.

However Court's husband said his wife was "advised not to attend" the Open this year, adding she's taking the chance to spend some time with her family. The pair have four children and nine grandchildren.

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