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Serena Williams tried to defuse her war of words with Maria Sharapova on Sunday as the Wimbledon champion claimed she had apologised to the Russian for criticising her private life.

Williams, a 16-time Grand Slam winner, infuriated Sharapova by making a thinly-veiled reference to the world number three's relationship with Bulgarian player Grigor Dimitrov, believed to be Serena's former boyfriend, during a recent interview with Rolling Stone magazine.

"She begins every interview with 'I'm so happy. I'm so lucky' -- it's so boring. She's still not going to be invited to the cool parties. And, hey, if she wants to be with the guy with a black heart, go for it," Serena was quoted as saying.

Sharapova was so upset by Serena's comments that she hit back on Saturday by drawing attention to the American's romance with her French coach Patrick Mouratoglou.

"If she wants to talk about something personal, maybe she should talk about her relationship and her boyfriend that was married and is getting a divorce and has kids," Sharapova said.

Sharapova also claimed she was "sad" that Williams made controversial comments in the same article regarding the rape of a 16-year-old girl by two high school American football players in the Ohio town of Steubenville.

But Serena, who starts her Wimbledon title defence against Luxembourg's Mandy Minella on Tuesday, refused to escalate the row with her rival on the eve of the grass-court Grand Slam.

The world number one said she sought out Sharapova to apologise at a WTA players' party in London last week.

"I feel like Maria, unfortunately, was inadvertently brought into a situation she should have never been brought into," Serena said.

"I'm the first person to apologise. I'm the first person to reach out to individuals and people if I feel that something may have hurt them or something may have been misconstrued.

"I personally talked to Maria at the player party. I said; 'Look, I want to personally apologise to you if you are offended by being brought into my situation. I want to take this moment to just pour myself, be open, say I'm very sorry for this whole situation'."

Serena, 31, was repeatedly asked about the controversy at Sunday's press conference, but she made a spirited attempt to deflect questions about any lingering bad blood between the pair.

"We always have great conversations, so I believe that she definitely did accept it (the apology)," Serena said.

"I'm not really gonna comment on that (Sharapova's reaction), whether I'm disturbed or not.

"I know she also said that I should definitely focus on the tennis here, and I feel like that is another thing I can definitely take her advice on.

"Maybe I wasn't focused enough in the past on tennis. I'm definitely going to try to focus on that for the next two weeks."

However, Williams, who has beaten the Russian 13 times in a row including the recent French Open final, hinted at the tension simmering beneath the surface when she suggested Sharapova's comments and a row with American player Sloane Stephens may have been attempts to unsettle her mentally.

"That can be one way to look at it," she added. I don't think about that, however. I just think about when I'm on the court."

Serena arrives at Wimbledon hoping to win the title for the sixth time and she conceded the storm over her interview had been less than ideal preparation.

"It definitely hasn't been easy. And I feel like I really wanted to say, I apologise for everything that was said in that article," she said.

"Everyone definitely has different regrets in different forms. For me, I take full responsibility.

"It's important what I've learnt this week, mostly that it's so important to know all the facts before you make a comment or before you make an assumption.

"That's something I'm still learning."