When Maria Sharapova says her game is getting better and better at Wimbledon, it's hard to argue.

The fifth-seeded Russian, the only quarterfinalist at the All England Club with a Grand Slam title to her name, dominated her match on Centre Court on Tuesday, moving back into the semifinals for the first time since 2006.

"I certainly feel like I've improved, especially from my second round," said Sharapova, who beat 24th-seeded Dominika Cibulkova 6-1, 6-1 on another wet day at Wimbledon. "I think that's really important if you want to get to the later stages, later stage of the second week, as well.

"You have to step it up because the matches will only get tougher and you're going to be playing better players that have won the same amount of matches, as well."

Sharapova won the Wimbledon title in 2004 when she was only 17. She made the semifinals the next two years, but hadn't been back this far since.

To reach a second final, she'll have to beat German wild-card entry Sabine Lisicki, who reached her first Grand Slam semifinal by defeating 2007 finalist Marion Bartoli 6-4, 6-7 (4), 6-1.

In the other semifinal match, fourth-seeded Victoria Azarenka will face Petra Kvitova.

On Wednesday, the men return to the court with six-time champion Roger Federer up against Jo-Wilfried Tsonga, defending champion Rafael Nadal against Mardy Fish, Novak Djokovic facing 18-year-old Australian qualifier Bernard Tomic and Andy Murray versus Feliciano Lopez.

Sharapova lost the opening game of her match under the roof on Centre Court, but then won eight straight and never let Cibulkova hold serve again.

"It's been a few years since I got past the fourth round, and now I'm in the semifinals," said Sharapova, who has not lost a set at this year's tournament. "So this a great chance for me to take it a step further."

Although Azarenka is the highest seeded player remaining in the draw at No. 4, Sharapova is the favorite.

At 24, the Russian is three years older than the other three semifinalists. Plus, Sharapova won the 2006 U.S. Open and the 2008 Australian Open while Lisicki and Azarenka will be playing in a major semifinal for the first time.

"It's great, the fact that I've had the experience of being in those stages. But I haven't been for a while, so it's a nice and refreshing feeling to have," Sharapova said. "I've put a lot of work in to get to this stage, but I still feel like, you know, the tournament's not over. I still have a few more goals left."

The first obstacle will be Lisicki, who was first up under the roof on Centre Court as rain poured down and thunder blared.

Despite wasting three match points in the second set, Lisicki held on to become only the second wild-card entry to reach the women's semifinals at the All England Club and the first German Grand Slam semifinalist since Steffi Graf in 1999.

"I cannot explain how I feel at the moment," said Lisicki, who missed much of the 2010 season following an ankle injury. "It was just such a tough road back and it's so wonderful to be standing on Centre Court in Wimbledon, which I love so much. I'm just so happy."

For Bartoli, the loss was a letdown after eliminating four-time champion Serena Williams in the previous round.

"I still beat Serena Williams in Wimbledon. I think I still can be proud of myself," said Bartoli, who tired after winning the second set. "Even though I lost today, it was still a good match. It was still a good fight."

The rain briefly delayed the start of play Tuesday as the roof was closed, while the opening match on Court 1 started after a 2½-hour delay.

Once it did, Kvitova reached the Wimbledon semifinals for the second year in a row, beating Tsvetana Pironkova of Bulgaria 6-3, 6-7 (5), 6-2.

"At the beginning I was better and I played so good like matches before," said the Czech, who had 54 winners to only 10 for Pironkova. "But then I get little nervous, and in my mind was something I don't know what was it. I was mentally down."

Azarenka defeated Tamira Paszek 6-3, 6-1 in a match that started on Court 1 but was moved to Centre Court because of rain after just one game.

In the second game of the second set, Azarenka pulled off a forehand winner on break point that didn't even have to clear the net. Instead, the Belarussian ran down a shot to her right and smacked it outside the post and into the court on the other side.

"It's actually my mom's birthday today so I really wanted to give her a good gift so I was really trying to play beautiful today and that was the first time I did this shot," Azarenka said. "So I'm really glad I could."