By Michelle Fleury
BBC World Business Report in Houston
Jeffrey Skilling, former chief executive of Enron, is due to take the stand in his own defence on Thursday.
Mr Skilling's (left) defence will be a key moment in the trial
The man who helped transform Enron into America's 7th largest company at its height, denies 28 counts of conspiracy and fraud related to its collapse.
He is charged - along with Enron founder Kenneth Lay - with hiding losses worth billion of dollars and lying to investors about its finances.
Experts believe Mr Skilling's testimony could make or break the case.
Mr Skilling's performance, and the strength of his arguments, will be seen as critical if the jury is to be convinced of his innocence.
"Mr Skilling needs to win an academy award," says Joel Androphy, a trial lawyer who has been watching the case in Houston.
"He just can't be good. He's got to be great."
Defence lawyers opened their case on Monday, after a series of prosecution witnesses testified that Mr Skilling and Mr Lay were aware of Enron's dire financial position prior to its collapse.
"At this point in time once Skilling testifies everything the prosecution did in the case is pushed aside," Mr Androphy adds. "All the deficiencies in the testimony, all the advantages. The focus is on the defendant."
Experts believe Mr Skilling's experience in the business world should help him in his defence, as he became well versed in marketing the company to investors and analysts.
"As a rule, most of these people are very comfortable being in the drivers seat," says Dr Richard Pesikoff, professor of psychiatry at Baylor College of Medicine.
"They are, in a sense, the CEO of the courtroom and so the spotlights are on them as they are at a board meeting where they are running the meeting and they're very familiar with answering questions."
Mr Skilling has always wanted to tell his side of the story.
When questioned by Congress in early 2002, he said he was devastated by what happened at Enron and blamed investors for the collapse.
Ken Lay is due to testify later this year
"It is my belief that Enron's failure was due to a classic run on the bank, a liquidity crisis spurred by a lack of confidence in the company," he said at the time.
That argument is being used by the defence which have said Enron was a healthy company that was done in by a financial market panic.
Mr Lay, Mr Skilling's boss at the time, is expected to testify later although his lead lawyer, Mike Ramsey, will miss much of the defence's case due to health problems.
While both men are keen to relate their version of events, their credibility will be on the line.
History is filled with examples of how testifying on your own behalf can backfire.
Bernie Ebbers, the former Worldcom boss who took the stand in his own defence, was convicted last year.
Many legal experts said after the case that he appeared to lack credibility.
In this instance, it appears the skills required to become a charismatic business leader didn't translate well with the jury.