Zimbabwe's ruling party and opposition say the Constitutional Court will hear the opposition's challenge to the presidential election results on August 22.
Opposition leader Nelson Chamisa narrowly lost to President Emmerson Mnangagwa but Chamisa's party alleges "gross mathematical errors". It seeks a fresh election or a declaration of Chamisa as the winner of the July 30 vote.
Mnangagwa's lawyers and the electoral commission have filed papers saying the case should be thrown out, claiming the opposition filed its challenge too late.
The court has 14 days from Friday's filing to rule. The inauguration is on hold until then.
The peaceful vote raised hopes that Zimbabwe faced a new era after the November departure of longtime leader Robert Mugabe, but scenes of the military dispersing opposition protesters have caused a chill.