Manafort trial opens with fiery charges from both sides Lawyers in the Manafort case offered opening arguments on Tuesday.

Lawyers in the case of former Trump campaign chairman Paul Manafort offered opening arguments on Tuesday in the first major trial brought by Special Counsel Robert Mueller, and both sides told jurors there was a liar at the heart of the case.

The government’s lawyers argued that liar was Manafort, a man they alleged had been living an opulent lifestyle, as if he was “above the law.” In his opening statement, federal prosecutor Uzo Asonye said the case, “boils down to one thing: Did Paul Manafort lie?”

Manafort’s defense team countered by pointing a finger at the prosecution’s star witness – and Manafort’s former deputy -- Richard Gates.

Gates, a longtime business associate of Manafort and a onetime senior Trump campaign aide, pleaded guilty in February to two felony counts: conspiracy against the U.S. and lying to federal authorities. Since then, Gates has cooperated with the special counsel and met with Mueller’s attorneys on multiple occasions, sources have told ABC News.

“Rick Gates had his hands in the cookie jar and he didn't want his boss to find out," defense lawyer Thomas Zehnle told the court, accusing Gates of being “willing to say anything to save himself.”

The sharp words marked a dramatic opening to the trial, in keeping with the notoriously fast-moving Eastern District Court of Virginia, which lawyers often refer to as home to the “rocket docket.” Judge T.S. Ellis said he planned to keep the trial moving, telling the legal teams he expected witnesses to begin taking the stand before the first trial day was done.

After seating a dozen jurors - six men and six women - and four alternates by early Tuesday afternoon, Judge Ellis called on the attorneys to deliver their opening arguments.

"The evidence will show that he knowingly filed false tax returns," Asonye said, accusing Manafort of lying to the IRS and his “bookkeepers” in order to hide millions of dollars from his work in Ukraine.

Asonye, who described Manafort’s “lavish lifestyle” in detail, alleged that Manafort held more than 30 bank accounts that “served no business purpose other than to receive and hide income.”

Manafort’s defense countered that the true culprit in the case is not Manafort, but Gates. Zehnle, one of Manafort’s attorneys, said Manafort’s only mistake was trusting his former business partner.

"It’s about Mr. Manafort placing his trust in the wrong person,” Zehnle said.

ABC News' Lucien Bruggeman, Katherine Faulders, and Allison Pecorin contributed reporting.