ATLANTIC CITY, N.J. — The scramble to become leaders in a U.S. sports betting market that doesn’t even exist yet is heating up.

Las Vegas-based Scientific Games Corp. joined a legal battle against British online betting firm William Hill over Scientific’s proposed acquisition of one of the firm’s rivals, British-based NYX Gaming.

William Hill threatened to use its stock in NYX Gaming to block its acquisition by Scientific Games.

Scientific Games filed a lawsuit Thursday in Nevada, making many of the same claims against William Hill that NXY did in its own suit filed against the firm a week earlier in New Jersey. Both accuse William Hill of trying to stifle competition, anticipating that the U.S. Supreme Court soon will legalize sports betting in the U.S.

The maneuvering takes place as the nation’s highest court prepares to hear a case brought by New Jersey that seeks to legalize sports betting. The state is taking aim at a 1992 law that forbids state-authorized sports gambling in all but four states that met a 1991 deadline to legalize it: Delaware, Montana, Nevada and Oregon. Nevada is the only state to allow single-game wagering.

Scientific Games asserted in its lawsuit that acquiring NYX would increase competition by combining NYX’s technology with its own status as “the largest lottery and gaming supplier in the U.S.” It said the newly combined company will provide more gambling and entertainment choices for customers, “which is exactly what William Hill fears.”

A spokesman for London-based William Hill did not immediately respond to a request for comment Saturday. But in response to NYX’s lawsuit last week, the company said it is simply looking out for the interests of its shareholders, and called its proposed restrictions on what the newly merged company can and can’t do “perfectly reasonable.”

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