LONDON,  (Reuters) – Sparks are expected to fly from  Serena Williams’s racket when she finally gets a chance to  settle a six-year-old score against Maria Sharapova today.

The last time they met on grass, Williams was a sure bet to  complete a hat-trick of Wimbledon crowns as she was facing a  virtually unknown 17-year-old in the 2004 women’s final.

But somebody obviously forgot to inform the Russian to tell  her about her bit part in the final, and instead she memorably  tried to ring up her mother from Centre Court to tell her “Hi  mum, guess what? I just won Wimbledon.”

Today, Williams, who stood stonefaced next to Sharapova  on that sun-drenched July afternoon during the presentation  ceremony, will be out to exact revenge and is confident there  will no longer be any nasty surprises in store for her.

“She really knows my game. I think she really studies it. I  pretty much know her game, so…” three-times champion Williams,  28, said looking ahead to eagerly-awaited showdown.

Williams has every right to feel confident as over the past  few months she has taken her grand slam tally to 12 while  Sharapova is still trying to work out how far she can stretch  her serving arm after enduring numerous shoulder problems.

But when two of the most recognisable faces in tennis and  hardest hitters face-off the world sits up to take notice and  Sharapova is no different.

“I love playing against her. I love playing against the  defending champion,” said the 16th seed, who won the last of her  three majors at the 2008 Australian Open.

“She’s great on this surface. If there’s a challenge ahead  of you, it’s definitely playing against her and I enjoy that.”

Sharapova also did not want to give too much significance to  her victory here in 2004 as since then Williams has opened a 5-2  lead in their match-ups.

“It’s tough to take anything away from our last meeting on  grass as it was many years ago,” said the 23-year-old, who  tuned-up for the grasscourt major with a runner-up finish in  Birmingham earlier this month.

“Serena and I know each other’s game pretty well now. Even  though we haven’t played in a while.

“She’s a really big hitter. She is a big server. You’ve got  to really take your chances when you have them. We certainly  have a good rivalry building up.