Mayor Brandon Johnson’s handpicked school board was blocked from modifying Chicago Public Schools CEO Pedro Martinez’s duties by a Cook County Judge on Tuesday, giving the embattled schools chief a victory as he battles with City Hall over the district’s future.

Chicago Mayor Brandon Johnson’s hand-picked school board voted Friday to fire Chicago Public Schools CEO Pedro Martinez, taking a step their predecessors had resisted and capping a months-long campaign by the mayor and teachers union to oust the schools chief.

A Cook County judge ruled in favor of embattled Chicago Public Schools CEO Pedro Martinez, stating that school board members cannot participate in negotiations with the Chicago Teachers Union unless invited by Martinez to do so.