Marcelo Bielsa admitted he had sent staff to spy on every team Leeds have played this season but defended his methods and insisted they were not illegal.
Bielsa called an impromptu press conference on Wednesday evening in response to investigations launched by the Football Association and the English Football League into his practices.
Derbyshire Police were forced to intervene last Thursday and move on a man, later confirmed to be an employee of Leeds, after Derby had reported him watching their training session.
Bielsa admitted before Leeds' home win against the Rams on Friday that he was behind the spy tactics and had called Derby boss Frank Lampard to accept full responsibility.
"I can tell you we observed all the rivals we played against and we watched all the training sessions of the opponents before we played against them," said Bielsa who proceeded to embark on an hour-long PowerPoint presentation.
"Regarding what I've done, it's not illegal. It's not specified, it's not described, it's not restrained. We can discuss it, it's not seen as a good thing, but it's not a violation of the law."
Leeds owner Andrea Radrizzani has since met with Derby counterpart Mel Morris to formally apologise and the club said they had reminded Bielsa of "the integrity and honesty which are the foundations that Leeds United is built on".
"I did it because it was not illegal and not violating a specific norm," Bielsa said.
"You have norms that are linked to habits, you have norms that are linked to social condemnation and you have norms linked to what the law says."
Bielsa has been heavily criticised by some rival managers and television pundits, while retaining the full support of others.
The 63-year-old said he was expecting to be punished by the FA and EFL, but felt compelled to give greater insight into his coaching methods in an effort to convince them he was not cheating.
He said all the information he gained from having rival clubs watched in training had already been gathered by his backroom staff's extensive research.
Bielsa also said a lot of it was not necessary when preparing his team.
"So why do we do that? Because we feel guilty if we don't work enough," he added. "Because it allows us not to have too much anxiety and we think by gathering information we feel we get closer to a win.
"In my case, it's because I'm stupid enough to allow myself this kind of behaviour.
"In a few words I will tell you something that is not easy to explain - how we analyse each opponent without having to watch their training session." Bielsa went on to reveal the extraordinary level of research which went into his match-day preparation.
Before Friday's game Bielsa and his staff had watched all of Derby's 51 games the previous season, with each match taking four hours to analyse.
All opponents' games are watched on video and broken down into five-minute spells to show which side is dominating, while Bielsa has data on every Championship player, including how many minutes each has played in certain positions.
Bielsa admitted he was embarrassed by the depth of his analysis, adding: "I know that people laugh at you when you create this much data.
"When you have strong data, it allows you to make a caricature of the one who is saying that."