Washington CNN  — 

The fifth day of former Trump campaign chairman Paul Manafort’s trial, after a weekend break, surprised the attendees in the courtroom when prosecutors called Manafort’s longtime deputy Rick Gates to testify.

Here are four takeaways from the afternoon in court Monday:

1. The day the courtroom was waiting for

Gates came out swinging from the witness box. Without smiling or pausing, he told the jury he had knowingly committed crimes “at Mr. Manafort’s direction.”

RELATED: Gates says he and Manafort didn’t report 15 foreign accounts, knew it was illegal

This was the testimony that close watchers of Manafort’s troubles have been waiting for since Gates flipped in February. Murmurs ran through the courtroom when prosecutors said they would call Gates to the stand at 4:15 pm, about an hour before the court proceedings typically end for the day. Gates, clean-shaven for his first public appearance since his guilty plea, did not look at his former boss, though Manafort followed his every step and answer.

“I was the one who helped organize the paperwork and initiate the wire transfers,” Gates said, describing Manafort’s use of unregistered Cypriot bank accounts to collect political consulting payments from Ukrainian oligarchs.

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Gates also said he had filed false expense reports when he worked for Manafort as a way to steal hundreds of thousands of dollars from those accounts.

The admissions from Manafort’s so-called “right-hand man” gripped the courtroom, even though much of them had been previously known.

2. Gearing up for Tuesday

Gates will return to finish testifying Tuesday morning at 9:30, in what may be the true fireworks of the trial.

When he finished speaking Monday, he had described his history of work with Manafort, his plea deal with prosecutors and how Manafort’s consulting operation in Ukraine functioned. While Gates had already admitted to knowingly hiding foreign accounts for Manafort, there are still a lot of details about alleged fraud in Manafort’s indictment that prosecutors will want to ask him about. Gates was closely involved in much of Manafort’s interactions with his accountants and the banks.

Prosecutors said they still have about three hours of questions for Gates. In that time, we’re also likely to see several emails and other documents with Gates’ and Manafort’s names on them as evidence.

3. The art of the cross

Once Gates has walked through all the prosecutors’ evidence, the defense will begin its questioning of him.

In what’s known as a cross-examination, defense attorneys get to hurl questions at witnesses that could make the jury doubt the certainty of the prosecutors’ case. For instance, on Monday, after federal financial crimes specialist Paula Liss testified that neither Manafort nor his wife had reported foreign bank accounts to her agency, FinCEN, defense attorney Tom Zehnle asked her if a person owning less than 51 percent of a company would need to report those accounts. She said no, explaining a technicality, and leaving the possibility hanging in the air that Manafort and his wife, who split ownership of DMP International, may not have needed to make the disclosures.

Earlier Monday afternoon, the defense dug in on its cross-examination of former Manafort accountant Cindy Laporta. The defense introduced its own documents to the jury for the first time – rather than relying on the prosecutors’ binders of evidence – and showed that Manafort had paid $8 million in taxes over 10 years.

Expect the defense’s time with Gates on the stand to be quite the clash, as the defense attorneys try to puncture his remaining credibility before the jury. The defense team is aiming to spin the crimes as Gates’ brainchildren.

4. Moving things along

What surprises could still be in store from the prosecution’s case?

The extent of witness testimony planned after Gates’ testimony ends is unclear.

Bankers are expected to take the stand, and four witnesses who’ve been given immunity by the court have yet to testify. Their testimony could be scintillating. One is a bank employee who appears ready to address an alleged deal between his boss and Manafort, after the bank executive sought a role in the Trump campaign.

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In theory, prosecutors will want momentum to build throughout the week, so the jurors are left with no doubt even as they hear the defense’s presentation.

The prosecution’s witness list still has 19 names of those who’ve yet to appear in court.

Judge T.S. Ellis has urged – harshly, at times, including on Monday – for the prosecutors to move their case along more quickly. Prosecutors said last week that they planned to finish sometime before the end of this week.

It’s not known yet how extensive a case Manafort’s team will present in his defense.