LOS ANGELES — Maria Sharapova muses on her long, lopsided rivalry with Serena Williams in a new autobiography released on Tuesday and how she believes a locker room moment fueled the American’s drive to dominate her.

The Russian-born Sharapova was 17 when she defeated Williams in the 2004 Wimbledon final. Rather than proving the start of a long, close-run rivalry, it was one of just two victories Sharapova can claim against the US great, who has beaten her 19 times.

In her new book, "Unstoppable: My Life So Far," Sharapova says it was not only her victory, but the fact that she overheard Williams weeping afterwards in the locker room that ensured the American would always find a way to elevate her game in their future contests.

"Guttural sobs, the sort that make you heave for air, the sort that scares you," Sharapova writes of the moment, according to excerpts released by The New York Times.

"It went on and on. I got out as quickly as I could, but she knew I was there. People often wonder why I have had so much trouble beating Serena; she’s owned me in the past ten years.

"I think Serena hated me for being the skinny kid who beat her, against all odds, at Wimbledon," she said.

In the memoir published by Sarah Crichton Books, an imprint of Farrar, Straus and Giroux, Sharapova details her tennis career from the time of her move to Florida at the age of six -- and Williams caught her attention early on.

Sharapova recalls surreptitiously watching Serena and her sister Venus play during a visit to the Florida academy where she trained -- unwilling even then to "put myself in the position of worshiping them, looking up, being a fan."

Tensions between Sharapova, a five-time Grand Slam champion who returned to competition in April after a 15-month doping ban, and 23-time Grand Slam champion Williams -- who gave birth to a daughter this month -- have sometimes spilled over into public spats.

Sharapova ponders the reasons, wondering if the antagonism between them has perhaps driven each to excellence.

"Maybe that’s better than being friends," she writes, adding: "Someday, when all this is in our past, maybe we’ll become friends. Or not. You never can tell." — AFP