Serena drawing strength from childbirth scares

More majors

Williams, a 23-time Grand Slam champion, told Vogue she is determined to win more major titles and surpass the record of 24 Slams held by Australia's Margaret Court. "Maybe this goes without saying, but it needs to be said in a powerful way: I absolutely want more Grand Slams," she said. "I'm well aware of the record books, unfortunately. It's not a secret that I have my sights on 25."

Williams said being a mother might boost rather than hinder her quest.

"Actually, I think having a baby might help," she said. "When I'm too anxious, I lose matches, and I feel like a lot of that anxiety disappeared when Olympia was born.

"Knowing I've got this beautiful baby to go home to makes me feel like I don't have to play another match," she said. "I don't need the money or the titles or the prestige. I want them, but I don't need them. That's a different feeling for me."

Sibling rivalry

In the interview, Williams also discussed her rivalry with her older sister, Venus, who enjoyed a resurgent 2017 and finished the year as world No 5.

"I know that her career might have been different if she had my health," Serena said. "I know how hard she works. I hate playing her because she gets this look on her face where she just looks sad if she's losing. Solemn. It breaks my heart.

"So when I play her now, I absolutely don't look at her, because if she gets that look, then I'll start feeling bad, and the next thing you know I'll be losing.

"I think that was the turning point in our rivalry, when I stopped looking at her."