The savage sledge that ignited Sharapova-Serena rivalry

Maria Sharapova has lifted the lid on an explosive sledge that kicked off her fierce feud with Serena Williams.

An extract from Sharapova's soon-to-be-released autobiography has been released online, and details how the long-running battle between the two stars started very early.

Sharapova recently returned from a 15-month doping ban, which she used to pen "Unstoppable: My Life So Far."

In the extract published by People Magazine, Sharapova recounts her very first match against Serena - a famous upset victory in the final of Wimbledon in 2004.

Sharapova was just 17 at the time and shocked the world to claim her first grand slam title.

Serena was incredibly gracious in defeat, laughing with Sharapova and smiling for the cameras in the trophy presentation.

NEW TOP DOG: Federer and Nadal take No.1 fight to Cincinnati

But according to Sharapova, she walked in on a devastated Serena in the locker room afterwards.

"When the match was over, Serena hugged me," Sharapova writes. "She said something like 'good job' and smiled. But she could not have been smiling on the inside."

"What I heard when I came in to the locker room was Serena Williams bawling. Guttural sobs. 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; my record against her is 2 and 19. To me, the answer was in this locker room.

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

"Not long after the tournament, I heard Serena told a friend – who then told me – 'I will never lose to that little b**** again'."

Sharapova believes her 2004 victory actually spurred Serena to greatness.

"Serena and I should be friends; we have the same passion. But we are not. I think, to some extent, we have driven each other. Maybe that’s what it takes.

"Only when you have that intense antagonism can you find the strength to finish her off. Who knows? Someday, when all this is in our past, maybe we’ll become friends."

35-year-old Williams has gone on to win 17 more grand slams since that loss in 2004, taking her record tally to 23.

Sharapova has won just four more, losing to Serena in three other grand slam finals.