Six years ago, as a bright-eyed 11-year-old at the Nick Bollettieri academy in Florida, Nicole Vaidisova played with the same yellow racket as Venus Williams, one of the players she most admired. Two years ago, having qualified for a Grand Slam tournament for the first time, the 15-year-old Czech was in awe as she shared a locker room with Williams at the US Open. Thirteen months ago, in Istanbul, the 16-year-old was learning her way on the senior tour when she won just five games in her first match against Williams.
Yesterday, only six weeks after celebrating her 17th birthday, Vaidisova underlined her status as one of the game's most exciting young talents when she followed up her victory over Amélie Mauresmo, the world No 1, by beating Williams 6-7, 6-1, 6-3 to reach the semi-finals of the French Open. The only surprise was that she took so long, having let slip the first set - in which she served six double faults - after taking a 4-1 lead.
Watching Vaidisova it is easy to forget that this is a teenager who would still have another year at school if she were not a professional sportswoman. She is 6ft tall, with broad shoulders and strong legs, and hammers the ball around the court - accompanied by a typical modern-day grunt - as if it were her worst enemy. She also conducts press conferences, speaking near-perfect English, with the assurance of a politician.
The quality of the world No 16's ground strokes forced a series of errors from Williams's racket. If there is a major weakness to the Czech's game it is her lack of confidence at the net, which Williams, who missed too many volleys of her own, was unable to exploit. The last game was typical as the American netted a routine volley and hit three forehands out of court.
Williams, who has played only 16 matches since last September's US Open because of an elbow injury, said she would go home to prepare for Wimbledon "in the same way that I've been doing for years". She added: "I just want to get stronger and better. With my arm doing better I can now practise my serve a lot more and you'll see that it will be more consistent at Wimbledon."
Vaidisova, whose entry for the Hastings Direct International Championships at Eastbourne in a fortnight's time was confirmed yesterday, now plays Svetlana Kuznetsova, who trailed her fellow Russian, Dinara Safina, 5-1 in the first set but then won 12 games in a row. Kuznetsova is enjoying her best year since winning the 2004 US Open, having reached five semi-finals and two finals already.
Tomorrow's other semi-final will pit Justine Henin-Hardenne, the defending champion, against her fellow Belgian, Kim Clijsters, for the 20th time. Clijsters leads 10-9, but Henin-Hardenne has won five of their last eight meetings.
Henin-Hardenne enjoyed a routine 7-5, 6-2 victory over Anna-Lena Groenefeld, while Clijsters had a surprisingly comfortable passage against Martina Hingis, winning 7-6, 6-1. Clijsters had won in three sets when they met at the same stage of the Australian Open earlier this year.
Hingis, who said she felt tired after four successive days on court, played with a lack of spark, though she forced a tie-break in the first set after trailing 5-2. The Swiss tried to take the game to Clijsters in the second set, but the Belgian responded with a succession of booming winners down the flanks.
"I'm very pleased to have made the quarter-finals again in a Grand Slam but you always want more," Hingis said. "It's just disappointing that I had a rough schedule over the last three or four days. I just didn't have enough time to recuperate. That's one thing I have to get used to. I'll hope for better times at Wimbledon."
Clijsters, looking ahead to tomorrow, described Henin-Hardenne as the game's best clay-court player. "I know I'll have to play aggressive tennis, similar to her. I think she's the best mover out there. She runs so many balls down.
"You have to play aggressively. She always makes you go for the extra shot," Clijsters said.
The first two men's quarter-finals went to form. Roger Federer, the No 1 seed, beat Mario Ancic 6-4, 6-3, 6-4 to earn a semi-final against David Nalbandian, the No 3 seed, who beat Nikolay Davydenko 6-2, 6-3, 2-6, 6-4. Nalbandian has won six of his 11 matches against Federer.
Ancic had treatment during the match for a shoulder injury and only occasionally had the world No 1 in trouble. Federer, who has dropped only one set here this year, said he felt in good shape to tackle tough challenges ahead. He and Nalbandian will have two days to prepare for their semi-final, one more than Rafael Nadal, provided the defending champion beats Novak Djokovic today.
Women's semi-final line-up: S Kuznetsova (Rus) v N Vaidisova (Cz Rep); K Clijsters (Bel) v J Henin-Hardenne (Bel).
Men's semi-final line-up: R Federer (Swit) v D Nalbandian (Arg); J Benneteau (Fr) or I Ljubicic (Croa) v N Djokovic (Serb-M) or R Nadal (Sp).