By Piers Newbery BBC Sport at Wimbledon

Sharapova's 2004 Wimbledon win is her only Grand Slam title

Maria Sharapova remains on course for a second Wimbledon title after a crushing win over Elena Dementieva in the quarter-finals on Tuesday.

The 2004 champion beat her fellow Russian 6-1 6-4 in the opening match on Centre Court.

After struggling to beat Flavia Pennetta on Monday, Sharapova was in determined mood and broke twice in both sets as she won in one hour 10 minutes.

She will play top seed Amelie Mauresmo in the last four on Thursday.

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"I knew that I needed to be really sharp today because I've always had tough battles against Elena," Sharapova told BBC Sport.

"I got off to a really good start, put a lot of pressure on her serves. I had a little bit of a let down in the second but I'm really happy to be in the semi-finals again."

Would I have liked that (the streaker) didn't do a cartwheel and run around the court for about 10 seconds? Yeah Maria Sharapova

Dementieva is a former French and US Open finalist but her weakness has always been a desperately fragile serve, and it proved the crucial factor again.

After putting a regulation forehand long having earned a break point in the opening game, Dementieva did the same when facing break point in the second.

And when she gave up another break in the following game with two double faults, the set disappeared soon after in just 27 minutes.

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The Centre Court crowd was keen to see a battle but Dementieva was being relentlessly forced backwards when her tame serves were hammered back.

She gave up successive service games to love as the second set got under way, before a streaker interrupted proceedings after 40 minutes.

It brought a smile from Dementieva, while a totally focused Sharapova simply turned away and ignored the sideshow.

After losing seven straight games, Dementieva got back to 4-3 down in the second set and had two break points for 4-4 but missed both returns on the forehand.

Her fleeting chance had gone and Sharapova held her firm after a nervous few minutes, sealing victory in her next service game.

And asked afterwards if she felt the security could have acted quicker to remove the streaker, Sharapova said: "Would I have liked that he didn't do a cartwheel and run around the court for about 10 seconds?