Prosecutor Bernie de la Rionda started today's court hearing by asking Judge Debra Nelson to have Serino's comment stricken from the record and the judge agreed.
Nelson ruled that one witness cannot offer an opinion of another and instructed the jury to disregard the exchange.
It remains to be seen if the prosecution's move actually drew more attention to Serino's testimony, or whether jurors will be able to ignore it.
De la Rionda moved to the heart of the state's case by asking Serino if Zimmerman's use of a crude epithet shortly before the shooting Martin showed ill will and spite. Zimmerman is charged with second degree murder and Florida law requires the state to prove a defendant acted with ill will, spite or hatred to convict on second degree murder.
"In your opinion calling somebody and referencing them, pardon my language, as f***ing punks ill will and spite?" asked de la Rionda. Zimmerman muttered the phrase while talking to the Sanford police dispatcher when he called to report Martin as a suspicious person.
"Yes sir, it is," responded Serino.
Courtroom theatrics punctuated the day with de la Rionda approaching Serino and mock punching him while asking Serino if he would have defended himself.
"if somebody is hitting would you have your hands like this or would you be fighting," the prosecutor asked as Serino looked back with some discomfort and answered, "I would be fighting you"
The lawyers took so many turns re-examining Serino, they were reprimanded by the exasperated judge. "You're about to go into re-re-redirect," she told the state.
Prosecutors allege that Zimmerman profiled and followed Martin who was returning to the home in the Retreat at Twin Lakes subdivision where he was staying as a guest. Zimmerman maintains that he did not follow Martin after a police dispatcher asked him to not follow the teenager. He said in taped interrogations that he got out of his car to get a house number for police who were en route to the scene.
"Isn't there a numerical address right in the front?" asked de la Rionda.
"Yes there is," responded Serino.
De la Rionda showed the jury images of Zimmerman's video re-enactment, which was filmed during the day, and the numerical address of a home where he got out of his car is visible. However, the incident occurred at night.
O'Mara brought up that there had been other burglaries in the community including the arrest of a young African-American who was arrested about two weeks before Martin's shooting.
But when asked by O'Mara, Serino said that he believed Zimmerman was in fact following Martin.
"Did you think there was anything wrong with following him to see where he was going?" asked O'Mara.
"Legally speaking no," responded Serino.
Tweeting from court, Sybrina Fulton, Martin's mother wrote "Day 17 - Remember God gives His toughest battles to His strongest soldiers. Please know I can't give up now. I've come too far. Continue to keep us lifted in prayer."