It is one of sport’s biggest rivalries and Maria Sharapova has opened up on a 2004 incident she believes triggered her feud with Serena Williams.

At the age of just 17, the Russian shot to prominence with a famous win against Williams in a dramatic Wimbledon final.

It was just the second meeting between the pair and sparked a rivalry that has been dominated by the American in recent years.

Williams has won all 18 clashes against Sharapova since 2005, a famous run that has included three grand slam finals and the gold medal match at the 2012 London Olympics.

Sharapova, who is soon to release her autobiography, Unstoppable: My Life So Far, said in the book that her 2004 win left Williams “bawling” and “crying” in the locker room.

“When the match was over, Serena hugged me,” she said.

“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 subs. I got out as quickly as I could, but she knew I was there.

“Not long after the tournament, I heard Serena told a friend – who then told me: “I will never lose to that little b…h again’.”

Sharapova, who returned to tennis from a 15-month doping ban in April, went on to say she is convinced that that defeat is why Williams and her have never been friends – and it is why the American has dominated their meetings since.

“People often wonder why I have had so much trouble beating Serena,” she said.

“My record against her is two 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.”

Sharapova, who has won five grand slam titles, added that she and Williams “should be friends”, given they share the same passion, but the pair have “driven each other” in recent years.

Sharapova – a former World No.1 – has dropped to 148th in the world rankings.

She has battled a left forearm injury since returning from suspension and has only played 10 WTA Tour matches this year.

Her best result in 2017 was a semi-final appearance in Stuttgart and she has not played at a grand slam this year.

Sharapova is hopeful of winning a wildcard to the final grand slam of 2017, the US Open, which begins on August 28.