MELBOURNE (AFP) -- An emotional Serena Williams on Saturday dedicated her third Australian Open title to half-sister Yetunde Price who was shot dead in Los Angeles in 2003, saying her memory motivated her to win.

"Most of all I would like to dedicate this win to my sister who's not here any more, Yetunde, I just love her so much," said Williams, who shocked the tennis world by thrashing top seed Maria Sharapova 6-1, 6-2. "I'll try not to be teary-eyed but a couple of days ago I said to myself that if I win this it's going to be for her -- so thanks 'Tunde."

Williams has a habit of writing notes during her matches on what she needs to work on, but on Saturday there was only word in her notebook -- Yetunde.

"Every day I write notes, you know, from my match. Not every day, but every match I wrote notes," she said.

"Today my note was just Yetunde. That was all my notes. That's it.

"Usually I write, 'look at the ball, move forward, do this, do that.' Today I just had one word.

"Every changeover I looked at it and I just thought about how happy she would have been, how much she always supported me. "I just thought about what an amazing sister she was to me. I just said, 'Serena, this has to be motivating. This has to be more than enough to motivate me'. And I think it was."

Price, a divorced mother-of-three, was shot in the head as she sat in her white sports utility vehicle outside a house suspected of drug activity in Compton, the gang heartland of Los Angeles.

The scene was not far from where her two youngest sisters, Venus and Serena, first played the game that would rocket them to international fame.

The bullet that struck Price was one of about 11 Robert Maxfield fired from an assault rifle to protect the drug house, jurors were told at his trial.

Maxfield, 25, pleaded no contest to the voluntary manslaughter of Price and last year was sentenced to 15 years in jail.

"I have so many good memories of my sister," added Williams.

"I remember just so many, so many things from her. "She was always so happy for me and Venus. She would come travel with us with her kids sometimes. You know, we had so many unbelievable memories. I take solace in those memories."

Venus and Serena are the youngest of five daughters raised by Richard Williams and Oracene Price, who are now divorced.

Three older daughters -- Yetunde, Isha and Lyndrea -- were the children of Oracene Price and a former husband, Yusef Rasheed.

Williams was written off by many pundits before the tournament after slipping to 81 in the world, and while she wanted to win for Yetunde, she was also driven by proving her critics wrong.

"It was an awesome win because I had so many critics, so many people talking bad and saying negative things and saying I wasn't fit when I felt that I was really fit and could last three sets and two-and-a-half or three hours, no worries," she said. "There's a great satisfaction holding up the Grand Slam trophy and proving everyone wrong."