MELBOURNE (REUTER) - German tennis queen Steffi Graf vowed on Wednesday to play through the Australian Open even if her father is found guilty of tax evasion and handed a prison sentence on the eve of the women`s final. Graf, the women`s world number one tennis player, told reporters after her second round match that she knew before coming to Melbourne that the tournament clashed with the possible date for the verdict in her father`s trial. "I knew already when I came here when the ending of the trial would be, and I`m playing until I`m done with this tournament," she said after her straight sets victory over Latvia`s Larisa Neiland. German prosecutors asked a court on Tuesday to jail Peter Graf for six years and nine months for tax evasion. Federal prosecutor Gabriele Schoepf told the Mannheim court in her closing remarks that Graf, 58, had tried to evade 19.2 million marks ($12.19 million) in tax on the tennis star`s earnings between 1989 and 1993. Schoepf asked the court to send Graf`s former tax adviser to prison as well. Steffi Graf, watched by her mother Heidi, trailed 5-2 in the first set on Wednesday before coming back to win 7-5 6-2. Pressed by journalists if the pending verdict was a contributing factor in her nervous start, she hesitated before replying: "No". The two men`s trial, which began last September, has attracted huge media interest. "I have been a little unfortunate, every time I play in grand slams, coming to difficult moments of everything happening," said Graf, who is competing for her fifth Australian Open title. Lawyers representing her father and her tax adviser will make their closing statements on Friday and Monday. The court, under German procedure, must then decide on a verdict and, if Graf is found guilty, a sentence. The verdict is expected on January 24. Steffi Graf herself remains under investigation in the affair but investigators have said suspicions against her are not as serious as those against her father. She has said she knew little about her financial affairs, entrusting them to her father from the start of a career which has taken her to the pinnacle of women`s tennis. Victory in Melbourne would see Graf`s career prize money rise beyond $20 million for the first time, just behind those of the now-retired Martina Navratilova. She has made many millions more in endorsement deals.