By Caroline Cheese

NICOLE VAIDISOVA PROFILE Born: 23 April 1989 in Nurnberg, Germany Lives: Prague, Czech Republic Height: 6ft Titles: 6 World ranking: 16 Did you know? Vaidisova's uncle is former top 50 player Daniel Vacek

Nicole Vaidisova may hide her youth behind some gritty play on the tennis court, but it is unmistakable in her post-match comments.

"I'm so excited I could just scream," enthused the 17-year-old after beating Venus Williams to reach her maiden Grand Slam semi-final at the French Open on Tuesday.

She revealed that, when she was 11, she had used the same racquet Williams played with and admitted she was "very excited" when she first saw her former idol in the locker room two years ago.

But Vaidisova showed little respect for Williams when she bundled the Wimbledon champion out in Paris, and had no sympathy for the nerve-struck world number one Amelie Mauresmo in the previous round.

Her fearless attitude will come as no surprise to those who have followed her career closely.

A German-born Czech, Vaidisova arrived at Nick Bollettieri's renowned academy in Florida when she was 10, accompanied by her stepfather and coach Ales Kodat.

Bollettieri was immediately impressed by Vaidisova's attitude, describing her, in his own inimitable way, as a "tough mama".

"No-one has to push her. She has the ambition to be the best in the world, and it's a driving force that comes through loud and clear," said the 74-year-old.

"She has that fire. She is a perfect example of the kind of person I like to be involved with."

Bollettieri's view was enough for sports marketing giant IMG to sign up the teenager and begin funding her progress even before she made her WTA Tour debut in 2004 at the age of 14.

Armed with a venomous serve and a brutal forehand, the 6ft Vaidisova wasted no time making an impact.

Vaidisova is becoming one of the photographers' favourites

At the end of 2004, she had already won two titles, the first in her only her fifth tournament at that level, and was ranked 77th in the world.

By the time she turned 16, she was ranked inside the top 40.

At the same age, Maria Sharapova was not even in the top 150, while Serena Williams was at 500 and Venus 184.

Inevitably, given that Vaidisova is tall, has blonde hair and is a talented teenager, comparisons have been drawn with Sharapova.

But as well as both being favourites for the photographers, Sharapova and Vaidisova share a similarly fierce will to win.

Asked to explain how she came back from a set down against Mauresmo and again against Williams, Vaidisova responded: "You're in the fourth round, quarter-finals of a Grand Slam, you're not just going to give up, say: 'Maybe I'll try next time.'

"You just give it your all, know you've given 100%."

Tutored by her stepfather, who Bollettieri describes simply as "the boss", Vaidisova is still working on what she says is "putting my game together".

But if her semi-final against the notoriously up-and-down Svetlana Kuznetsova comes down to mental fortitude, there will be only one winner.

"At this point there's not one tactical thing that's going to get you further," she said.