Circuit Judge Debra Nelson rejected a defense motion for a directed verdict of acquittal, opening the way for Zimmerman's attorneys to begin presenting their case with Zimmerman's mother as the first witness.
Gladys Zimmerman testified the voice on the 911 tape calling for help was that of "my son George," contradicting testimony from Trayvon's mother and brother who testified it was the 17-year-old screaming for help.
Zimmerman's uncle Jorge Meza, an Orange County Courthouse deputy, also identified the voice as Zimmerman's, the Orlando Sentinel reported.
Prosecutor Bernie de la Rionda played a 911 call recorded just before Trayvon was killed in which yelling can be heard in the background.
"Ma'am, that screaming or yelling, do you recognize that?" de la Rionda asked Sybrina Fulton, Trayvon's mother.
Fulton answered yes, and identified it as her son.
Trayvon's older brother, Jahvaris Fulton, testified he recognized his brother's voice on the tape.
Dr. Shiping Bao, who performed the autopsy on Trayvon, testified he did not die immediately and may have suffered for as long as 10 minutes. Bao was the state's last witness.
Defense attorneys have not yet said whether Zimmerman will testify.
Zimmerman pleaded not guilty to second-degree murder in the February 2012 killing during a confrontation as Trayvon walked to his father's home from a convenience store.
Testimony was to resume Monday.