Fantasy sports site operator DraftKings on Wednesday enlisted power attorney David Boies as it and FanDuel, a rival site with which it had hoped to merge, battled to have a potential class action suit brought by players dismissed in federal court in Boston.

The merger plans were dropped Thursday. “Under the facts of this case and the absolutely clear, four-square Supreme Court precedent, there is no basis for attacking the arbitration clause in this case,” Boies said in a filing.