Men’s professional tennis faces a trial from today that may not only break it financially but will also probably cost Etienne de Villiers, its leader since January 2006, his position as chairman and president of the ATP, whatever the outcome.

Moves are under way to replace the former Disney executive whether or not the governing body beats off the German federation’s suit for damages for what it terms an “illegal, anti- competitive arrangement” to demote the Hamburg clay-court tournament from Masters status from next year.

De Villiers, the 57-year-old South African whose contract expires at the end of this year, suffered a setback last month when Roger Federer, Rafael Nadal and Novak Djokovic were elected to the ATP’s player council. It was the first time that the world’s top three have chosen to become so politically involved in the game, and came about because they have been critical of De Villiers’ “brave new world” for men’s tennis, in which Hamburg loses the status it has enjoyed since 1990.

Toni Nadal, the Wimbledon champion’s uncle and coach, stirred the pot in May, when he called for the chairman’s head. Then Ivan Ljubicic, the Croat who has been promoted to the ATP Board as an interim player representative until next month’s US Open, was asked about De Villiers’ position at Wimbledon. “The day the decision \ is announced, the phones are going to be hot,” he said. “That’s when we need to talk to each other and really see where we go from there.” Would the chairman’s position be discussed? “Definitely,” he replied.

De Villiers has flown to Wilmington, Delaware, for the two-week court case, which the ATP cannot afford to lose, in all senses. It is suggested that the lawsuit could become a landmark for professional sports in determining the authority of governing bodies and what rights an organisation such as the ATP has in shaping its calendar and protecting commercial interests. “In terms of how it impacts players and cities with tournaments, it has the potential to change the face of the game,” Richard Fields, a veteran

New York attorney, said.

When initial plans for the tour’s restructuring were announced, it was to the effect that the Monte Carlo and Hamburg clay-court events would become second-tier tournaments. Both sued — Monte Carlo settling for a compromise in which it would offer the same number of ranking points (1,000) as the other eight Masters tournaments, but without the rule that forces the top eight players to appear or face financial penalties.

There have been at least half a dozen attempts at mediation, but Hamburg and its backers — which include the Qatar tennis federation, which bought the women’s Berlin Open in 2005 and is said to be offering “both moral and financial” support — have refused to budge. The ATP is alleged to have spent more than $7 million (about £3.5 million) in legal fees and the damages sought exceed its assets of $62 million as at the end of 2006.

It is understood that persuasive pressure has been applied to the ATP to settle, but the body remains steadfast in its belief that it is in the right. “We are ready to the last minute to settle this amicably,” an ATP spokesman said. “It is safe to say that there is a keen interest in the outcome from everyone in tennis, but at the heart of this is whether we, as a body, can decide on appropriate categories of tournament and set a calendar.”

The ATP insists that what it has done will “unlock more potential and deliver more value across the spectrum of the sport”. It says that more than $1 billion of investment is waiting to be pumped into men’s tennis and that Hamburg is earmarked as one of the ten 500-point tournaments (ie, the second division) and is promised a summer slot.

The litigation involves four claims against six named defendants — De Villiers, his fellow board members, Charlie Pasarell, Graham Pearce and Iggy Jovanovic, and two former members, Perry Rogers and Jacco Eltingh, who lost their positions two months ago.

“We remain very confident of our position,” the ATP spokesman said. Fields, on the other hand, has said that Hamburg has a very strong case. He added: “The Germans could end up owning the game of tennis before it’s all over. The ATP won’t exist in its present form if they lose this case.”

Etienne de Villiers

- Born in Pretoria, South Africa. Graduated from the University of Pretoria in 1970 with a degree in civil engineering. Received a Rhodes scholarship and read politics, philosophy and economics at Oxford University from 1971 until 1974.

- Served from 1986 to 2000 in a variety of senior executive capacities for The Walt Disney Company, including president and managing director of Walt Disney International Europe.

- De Villiers was appointed non-executive chairman of the ATP in 2005. Assumed broader, full-time responsibilities as executive chairman/president a year later, focusing on strategy and board governance.

- Non-executive chairman of BBC Worldwide and holds non-executive directorships, including Jetix Europe, Video Networks Ltd and Private Investor Capital Ltd. Underwent prostate cancer surgery in 2005.