Graf judged on the court

The world No 1 Steffi Graf continues to astonish even those closest to her with an amazing ability to keep winning while her personal world is falling apart.

Once again on Saturday, just two days after the start of her father's trial on tax evasion charges, Graf managed to keep her focus on tennis long enough to score a 7-5, 6-3 win over the Swiss teenager, Martina Hingis, and advance to her fourth consecutive US Open final.

"How she goes and pulls it together... if I knew the recipe I would be the greatest coach in the world," Heinz Gunthardt, Graf's coach, said with wonder and admiration.

Peter Graf, once a constant presence at all her matches, has been in prison for more than a year on suspicion of failing to pay approximately $13m in taxes on his daughter's tennis earnings.

The trial began on Thursday with the tennis player's father facing a possible 10 years in prison if convicted. Graf herself remains under investigation, and while her father insists she knew nothing of his handling of her vast tennis earnings, co-defendant and former Graf family accountant Joachim Eckardt testified on Friday that the 27-year-old player knew all about the financial dealings.

"I know it has been very difficult for her the entire time, but more now than ever before," Gunthardt said of Graf, who has still won three Grand Slam titles with her father behind bars.

"She does have lapses in practice and days when she is not well off. Sometimes she can't get her head together on court. Five minutes she will hit well and she then will hit it all over the place. It makes it very difficult for her to practice," Gunthardt said.

That may account for Graf's difficulty in the first set of each match throughout her 1996 US Open campaign as she struggles to find her concentration in the early stages.

"I am usually somebody that starts well from the beginning on, so that is not my character," admitted Graf, who had to stave off five set points in the first set against Hingis.

"Not one of those set points she saved can you say she got a present from Hingis," said Gunthardt. "You can't say Hingis choked. At the crunch time Steffi knuckled down. That's the mark of a champion."