Tokyo: World number one Maria Sharapova struggled with her serve again but beat Japan's ace Ai Sugiyama for a place in the semi-finals at the Pan Pacific Open tennis tournament on today (Feb 2, 2007).

The Russian top seed, who hit 17 double faults in three sets Thursday, committed another 14 double faults before finally fending off the challenge from Sugiyama 4-6, 6-0, 6-1.

"I felt worried about my serve too much in the first set. That was the reason for me not being aggressive enough. Obviously some part of my game was off and in this tournament it's my serve," said Sharapova.

"But I thought I did a good job just focusing on what I have to do, even if I gave her many free points off my serve.

"I played enough matches in the last couple of weeks. To know getting into a Grand Slam final (at the Australian Open) definitely gave me some confidence," added the US Open champion.

The 19-year-old Russian, the winner here in 2005, failed to keep a service break up in the beginning as she hit her third double fault on a break point to be tied at three games.

Sharapova hit another double fault to go into a deuce in the 10th game, which eventually Sugiyama won with an excellent backhand shot down the line.

But that was all the Japanese could do as Sharapova, who only lost the second game of the final set, completely dominated the remainder of the 87-minute match.

"She was playing aggressive tennis in the first set, and I wasn't really going for my shots. She was taking the ball earlier, was getting around all the time to hit her things and she did it very well," said Sharapova.

"Michael (Joyce, her coach) told me to 'step in and go for it a little bit more, and I just started playing aggressive tennis. I didn't get her enough time which she likes to do."

Sugiyama said she had some success moving the Russian around in the first set, but that was all.

"From the second set, she just raised her game. She was dominating. She was just perfect," Sugiyama said.

"I should have taken those chances more, because she hit so many double faults. But she never made errors with her strokes. In the end, she showed the difference between the world number one and me."

In the semi-finals Saturday, Sharapova will take on fifth seed Ana Ivanovic of Serbia, who eliminated her compatriot and fourth seed Jelena Jankovic 3-6, 6-4, 6-2.