By Jonathan Stempel

NEW YORK (Reuters) - A federal appeals court has upheld a reorganization of the ATP Tour, rejecting antitrust claims over the downgrading of a Hamburg, Germany, tennis tournament.

Friday's ruling by a unanimous three-judge panel of the U.S. Third Circuit Court of Appeals in Philadelphia affirmed a 2008 jury verdict favoring the Association of Tennis Professionals, which operates a men's professional tennis circuit.

The 2007 lawsuit by the German Tennis Federation and Qatar Tennis Federation, which co-owned the Hamburg event, arose from the ATP's decision to lower the clay-court tournament's status and move it from May, when it had been a French Open tune-up.

These changes stemmed from ATP's "Brave New World" plan to channel top players to top tournaments, and boost the tour's popularity, ticket sales, sponsorships and television reach. A lowering of a tournament's status entailed changes in ranking points and minimum prize money.

In a 45-page ruling, Judge Anthony Scirica wrote for the Third Circuit panel that while "professional sports teams or tournaments always have an interest in obtaining the best players possible," the federations failed to prove any conspiracy to monopolize a market for top-tier male players.

Scirica also wrote that the ATP board of directors did not breach any duty of loyalty because it had not been "materially self-interested" when it voted for the Brave New World plan.

Robert MacGill, a lawyer representing the federations, did not immediately return a call seeking comment.

The case is Deutscher Tennis Bund et al v. ATP Tour Inc et al, U.S. Third Circuit Court of Appeals, No. 08-4123.

(Reporting by Jonathan Stempel, editing by Matthew Lewis)