March 29 (Bloomberg) -- The ATP Tour, the governing body of men's professional tennis, was sued by organizers of the Hamburg Masters tournament to block a plan to downgrade their event's status.

The not-for-profit German Tennis Federation and Rothembaum Sports GmbH filed the lawsuit today in U.S. District Court in Wilmington, Delaware. They asked a judge to stop the tour from stripping Hamburg of its Masters status, which would make it harder for the tournament to attract top players. Spain's Tommy Robredo, the world No. 6, won the event last year.

The ATP's so-called Brave New World plan, to be implemented in 2009, is ``anticompetitive,'' violates U.S. antitrust laws and resembles an ``illegal cartel,'' the Hamburg organizers said in the complaint. An event in Monte Carlo also will probably lose its Masters status, they said.

``The ATP has artificially taken control of the supply of men's professional tennis players and of men's professional tennis tournaments,'' the plaintiffs said. ``It has done so to establish a favored class of tournaments, in which the ATP has a significant proprietary interest, while relegating all of the ATP's other member tournaments to a disfavored status.''

ATP President Etienne de Villiers is restructuring the men's calendar to reduce injuries and ensure top players take part in the most-prestigious events. The Masters series is a level below the Grand Slams such as Wimbledon and the U.S. Open.

ATP Response

The ATP, based in Ponte Vedra Beach, Florida, said it reviewed the complaint.

``The ATP is confident in its position and will continue to take steps to improve and grow its men's professional tennis circuit for the benefit of fans,'' Nicola Arzani, vice president of media and marketing, said in an e-mailed statement.

In the past year, the ATP introduced round-robin tournaments, play on Sundays at some events and instant replay to settle disputed line calls. Round-robin play was dropped this month.

Last year, a group of doubles players sought a court order to stop the ATP from implementing scoring changes aimed at shortening matches. The players said the move would eventually get rid of doubles specialists. The dispute was settled out of court.

According to today's suit, the 2009 calendar would create three tiers of ATP tournaments: The Masters Cup and Masters Series 1000, Masters Series 500 and the ATP 250. There would be eight Masters Series tournaments instead of the current nine. Shanghai was confirmed as one this week.

Minor League

Apart from the Masters Cup and Masters Series 1000, the other events, including the one in Hamburg, will be relegated as a ``minor league'' unable to attract elite players. Roger Federer and Rafael Nadal, the world's top two, pulled out of last year's tournament because they played a five-hour final the week before at the Italian Open in Rome.

This year marks the 101st edition of the Hamburg tournament. It's scheduled for May 14-20, a week before the French Open in Paris. The Monte Carlo tournament, also a clay- court tune-up for the French Open, was first held in 1897.

According to media reports, about 60 players, including Federer and Andy Roddick, signed a petition last week against changes to reduce European spring Masters events from three -- Rome is the other -- to two.

Madrid, announced by the women's WTA Tour this week as a combined event with the men, and Rome will probably fill those slots, Canada's Globe & Mail newspaper reported.

The case is Deutscher Tennis Bund v. ATP Tour, Inc., et al, 7CV178, U.S. District Court, Delaware (Wilmington).

To contact the reporter on this story: Ravi Ubha in London at rubha@bloomberg.net.

Last Updated: March 29, 2007 16:30 EDT