Dikshit's political secretary Pawan Khera filed the defamation case against Kejriwal for making "derogatory remarks" and "baseless" allegations against her in 2012.
He said Kejriwal used "false and filthy" language against Dikshit in a TV show.
The court, framing charges against Kejriwal, had said prima facie defamation charges were made against him and put the Aam Aadmi Party leader on trial after he pleaded not guilty.
Pleading not guilty, Kejriwal had said the complainant was not an aggrieved person and the complaint against him was false.
He opposed the complaint saying it was filed by Khera, and not by Dikshit.
He said if Dikshit was defamed, then she should have filed the case herself.
The AAP leader said Khera had no locus standi to file the case as he did not say anything against the political secretary, and only an aggrieved person can file a defamation complaint.