Before today's first witness entered court, Trump attorney Chris Kise asked Judge Engoron to postpone today's proceedings after five members of the New York attorney general's team tested positive for COVID-19.

Describing the attorney general's conduct as "beyond irresponsible," Kise said that his team did not get adequate notice about the COVID exposures despite having close contact with positive individuals.

"Nothing else matters except for pursuing President Trump," Kise said. "We have the leading candidate for president of the United States in the courtroom today."

"The attorney general's office knew on Wednesday and didn't tell any of us," defense attorney Clifford Robert said. "We are truly in an outbreak."

Engoron declined to grant their requested delay.

In a statement, a spokesperson for New York Attorney General Letitia James said the state has complied with all CDC guidelines.

"Our office properly notified the court and defendants' counsel, and the court decided to proceed with trial today. If there were any concerns, defendants could wear masks today or at any point, but they have opted not to," the spokesperson said.

Trump called his former lawyer Michael Cohen a "proven liar" and "felon" as Trump entered the courtroom for his civil trial this morning.

"He's a felon, served a lot of time for lying, and we're just going to go in and see and I think you'll see that for yourself," Trump told reporters outside court.

Cohen pleaded guilty in 2018 to two separate criminal cases and eventually spent more than 13 months in prison -- but said that it was Trump who caused him to "follow a path of darkness."

-ABC News' Ricardo Montero contributed to this report.

Exiting his New York City apartment this morning, Michael Cohen told reporters he was "looking forward" to seeing Trump in court.

"It's been five years since we've been in the same room," Cohen said.

Cohen preemptively defended the credibility of his testimony and reiterated that he previously perjured himself "concert with and for the benefit of Donald J. Trump."

"My credibility should not be in question," Cohen said.

-ABC News' Eric Avram contributed to this report.

Donald Trump has arrived in court for the anticipated testimony of his former lawyer Michael Cohen.

New York Attorney General Letitia James is also attending the trial this morning.

James took her usual seat at the front of the courtroom's gallery, directly behind her team of lawyers at the counsel table.

The courtroom itself is nearly at capacity, with attendance matching the number of observers during the trial's opening statements.

The second day of testimony from the defense's expert accounting witness prompted an argument between attorneys for the two sides over the basic question of what the case is about -- leading defense lawyers to make their fourth unsuccessful request for a directed verdict to end the trial.

The arguments came toward the end of direct testimony by accounting expert defense Eli Bartov, who asserted the New York attorney general's case lacked merit because there was no evidence of any fraud on Trump's statements of financial condition, and that any errors about the values of Trump's properties were unintentional and therefore immaterial.

When the defense attempted to question Bartov about those values, state attorneys objected -- prompting defense attorney Christopher Kise to leap from his seat.

"If they don't call anyone to dispute our values, how have they proven their case?" Kise said.

Judge Arthur Engoron, in a pretrial ruling, already decided that Trump conducted a decade's worth of business using fraudulent financial statements, and state attorney Kevin Wallace suggested that Bartov's findings do not change those findings.

"You can't use false statements in business. That's what the summary judgment decision is all about. I think it is pretty much what the rest of this case is about," Engoron said in response to Kise's question.

Kise argued that if the attorney general doesn't prove what Trump's asset values should have been, the case is a "completely rudderless ship" that needs to be "moored to some sort of standard."

"You can't just say it's a misstatement because you feel like it," Kise argued.

"The standard is truth," Engoron responded.

The exchange prompted Trump's legal spokesperson, Alina Habba, to make the defense's fourth motion for a directed verdict, arguing that Engoron is "wasting our time" if he won't consider their expert testimony.

"They have not proven their case. They haven't," Habba said in her request for a directed verdict.

"Denied," Engoron said within seconds of the request, without hearing a response from lawyers for the New York attorney general.