Russian Vera Zvonareva, Czech Petra Kvitova and Bulgarian Tsvetana Pironkova -- names that are barely household names in their native towns let alone in the wider world -- earned their golden tickets to the semi-finals after a day of topsy-turvy tennis at Wimbledon on Tuesday.

A look at the three Eastern European challengers ahead of their semi-final matches:

Tsvetana Pironkova used to think playing tennis on grass was impossible. Not any more.

The 22-year-old Bulgarian produced a dazzling display on Tuesday to destroy one of the game's greatest ever exponents of the grasscourt arts and reach the Wimbledon semi-final.

Her 6-2, 6-3 victory over five-times Wimbledon champion Venus Williams ranked as one of the biggest shocks in this year's tournament and was the worst defeat the American had ever suffered at the All England Club.

Not bad for a player who grew up in a country where tennis is played almost entirely on hardcourts and clay.

"We have no grasscourts actually," Pironkova told reporters when asked about her credentials on the game's quickest surface.

"I'm not sure which year it was (I first played on grass). I think it was five years ago here at Wimbledon at the qualifiers.

"Back then, I thought, wow, it's impossible. How can I play on this surface? But with every match that I play on grass I feel better and better."

Pironkova, ranked 80 places below world number two Williams, had form against the American.

She beat her in the first round of the Australian Open in 2006 only to crash out in the next round.

Until arriving at Wimbledon this year Pironkova had never lasted beyond the second round of a major but now believes she is ready to seize her chance.

"I can say that I'm ready. I beat Williams once before, at the Australian Open, like five years ago. There was so much attention then. I was shocked," she said.

"Next match, I just couldn't focus because of all the attention. Right now I think I've learned my lesson."

With her ready smile, graciousness in victory and affable answers, Pironkova has all the makings of a media darling -- a refreshing new face on the block.

"I can say that I gained my confidence last couple of years. I've learned a lot. I've been through a lot last year. I had a bad season. I learned a lot from that," added the Plovdiv native whose father was a champion canoeist.

Pironkova's willingness to accept the media glare is probably a good thing because she is the first Bulgarian to reach the semi-final of a Grand Slam in the open era.

It is a feat which eclipses the country's best-known tennis players -- the Maleeva sisters, although the oldest, Manuela, twice reached the last four of US Open competing under the Swiss flag.

"Wimbledon has always been like a religion to me," Pironkova said. "Growing up, every player is looking at Wimbledon. They say, 'one day I want to play there'.

"I still cannot believe that I reached the semi-finals. This is truly like a dream to me and I will try to enjoy it as much as I can," added the Bulgarian.

Photographs: Reuters

Vera Zvonareva wrapped herself in a cocoon of such fierce concentration on Tuesday that she remained the only person on Centre Court unaware of the identity of her Wimbledon semi-final opponent.

During the breaks in her 3-6, 6-4, 6-2 quarter-final upset of eighth seed Kim Clijsters, the Russian sat immobile in her chair with a towel enveloping her head.

As a result she did not see the screen carrying the scores from other matches which revealed that she will play Bulgarian Tsvetana Pironkova and not Venus Williams in the semis. Nor did she hear the surprised gasps from the crowd.

"I put the towel on because it just helps me to relax and not to see what is going on around," Zvonareva told a news conference.

"If you see all the things around, noticing all the scores, it just takes your concentration a little bit away and then maybe you will make a wrong decision on the court."

The opening match of the day on Centre Court began under overcast skies with a sprinkling of rain. Zvonareva was similarly subdued and one break of serve was enough to give Clijsters the set.

As the sun emerged, Zvonareva blossomed. She fought her way back in a series of savage backcourt rallies with a tenacious backhand which won generous praise from US Open champoin Clijsters.

"It's very hard to read the shot," she said. "Especially when she goes down the line, you can't even read it.

"I was trying to go for the lines but it's not easy when they're coming that hard and deep."

Zvonareva, whose best result previously at a Grand Slam tournament was a semi-final spot at the 2009 Australian Open, said she now has the maturity to play one point at a time.

"I was trying to stay concentrated, keep my concentration on all the time, trying to think what I will do on my next point," she said.

"Nothing else was bothering me, I wasn't noticing anything around. I'm much more experienced right now, much more mature.

"Even after I lost the first set, maybe there were a couple of unforced errors that could have put me back but I was trying not to think about it, I was trying to think about what I have to do to win the next point."

Unseeded Petra Kvitova from the Czech Republic will attempt to emulate her childhood idol Martina Navratilova by winning the Wimbledon women's title after saving five match points to clinch a place in the semi-finals.

Kvitova, who had never previously won a match on Wimbledon's grass courts, defeated Estonian qualifier Kaia Kanepi 4-6, 7-6, 8-6 after trailing 4-0 in the final set.

At a post-match news conference, Kvitova said she had spoken to record nine-times Wimbledon champion Navratilova, who was also left-hander, after the match.

"She is a legend. She was my idol when I was a small child," she said.

Kvitova, sensing her opponent's increasing anxiety in the closing set, broke in the 13th game before serving out to love after two hours and 39 minutes.

"At the beginning of the third set, I was really down," she said. "But I just knew that she could make some mistakes and that was my chance."

Kvitova will play defending champion Serena Williams for a place in Saturday's final.

Kanepi said she thought the match had been evenly balanced.

"It was 50-50," she said. "Obviously I was disappointed but I had to keep playing."

The tennis players Kvitova most admires are Roger Federer and Maria Sharapova, while other sports interests include basketball, volleyball.