Three of Europe's major online gambling groups have fended off a legal challenge from the organisers of the French Open tennis championships who wanted to stop bets on the Grand Slam tournament.

The Fédération Française de Tennis has claimed that online bookmakers Ladbrokes, Betfair and Bwin were violating French rights by offering bets on Roland Garros tournament matches.

The federation also said online betting has tarnished the reputation of the championship.

However, a landmark ruling delivered by a Belgian court in Liège said the operators continue to behave in a "prudent and diligent" manner.