PARIS – A retired French colonel accused of trying to boost his children’s tennis results by drugging their opponents admitted yesterday that he spiked the water bottle of a rival player who later died in a car crash.

Christophe Fauviau, whose 15-year-old daughter Valentine is one of France’s brightest prospects, made his confession at the opening of his trial in the southwestern town of Mont-de-Marsan.

In a case that has alarmed the tennis world, Mr. Fauviau is charged with the manslaughter of Alexandre Lagardere by unintentionally causing him to fall asleep at the wheel of his car. Lagardere had earlier been overcome by drowsiness while playing Mr. Fauviau’s son, Maxime, in the final of a local tennis tournament.

Mr. Fauviau, 46, a former helicopter pilot instructor with an exemplary military record, is also accused of administering toxic substances to 21 of Valentine’s opponents and six of her brother’s.

He was arrested in August 2003 at Dax railway station close to his home in Tercis-les-Bains, near Biarritz, after flying home from watching his daughter compete in Egypt.

There is no suggestion that either Valentine or her brother, who was 16 at the time of Lagardere’s death, had any knowledge of what their father was doing.

Valentine has risen above the allegations against her father by continuing her climb to the top, last year winning two junior titles and attracting plaudits for her “outstanding” play. Her brother was never considered more than a good regional player.

Mr. Fauviau, who faces up to 20 years in jail, told the court he resorted to drugging opponents with the anti-anxiety drug Temesta because “I felt I was permanently being judged by my children’s performances”.

He admitted that he had also applied Temesta, which he carried to calm his own nerves, to at least two other players. But he said his memory of the time was poor and suggested that the number alleged by the prosecution, covering a three-year period, seemed “too high”.

“I was not at all well at the time,” he told the court.”Each match was a terrible strain for me.”

Defense lawyers are expected to challenge the link between the Temesta taken by Lagardere, 25, a primary school teacher, and his accident six hours later.

In court yesterday Mr.Fauviau begged for the forgiveness of Mr.Lagardere’s parents “if it is the case that I am responsible for he death of their son.”

Other opponents suffered various symptoms including weak knees, dizziness, nausea, or fainting. Some needed hospital treatment.

Mr. Fauviau was allegedly seen by one of his intended victims tampering with his water bottle in the dressing room. Tests revealed the presence of Temesta, which was also found in Lagardere’s body. After his match against Maxime, Lagardere had complained of fatigue and slept for two hours before setting off home.

The case continues.