"If I were to say what I really think I would be arrested or shut away in a lunatic asylum. Come on, I'm sure that it would be the same for everyone."

On insanity, few have been more veracious than the Chilean writer Roberto Bolaño. In his own inimitable way the nomadic novelist and poet acknowledged what others often refuse to see; that we are all unhinged in our own delicate fashion. To some extent we will freely admit to our peculiarities, but largely our madness is defined by those around us, who witness our behaviour and for reasons of comfort believe it to be more abnormal than their own. How strange it is to be denied even the possession and enjoyment of our own madness by people who yearn to tell us that, yes, we are certainly mad. 

Bolaño died of a long illness in 2003 at the young age of 50. Four years later Chile had a new icon of insanity, as Marcelo Bielsa was appointed manager of the national team following a three-year hiatus from the game. How Bielsa had spent his prolonged absence remained a mystery to many, but upon his return it was reassuring to see that nothing had changed. Obsessive, compulsive and still Loco, as everyone wished him to be.

'What could be more foolish in this life than having a passion for football?' wrote Chilean journalist Patricio Navea before Bielsa's arrival. 'Only those of us who wept with Caszely's penalty or shouted every goal scored by the Za Sa duo, or simply wake up in a good mood the Monday after our team has won can understand this. Football is like religion. Those without faith don't get it.'

Even more so would they struggle to understand Bielsa, an obsessive whose cult of personality had grown through anecdotal evidence attesting to his madness. This was a coach who had taken 1,800 video tapes to the World Cup in 2002 when he was manager of Argentina and, after deciding that wasn't enough, requested that a further 200 be flown out to Japan. 

Chileans were familiar with Bielsa's habits owing to his Argentina tenure and previous spells at Newell's Old Boys and Velez Sarsfield. He arrived with a reputation for being intense, occasionally with a ferocious temper, and above all having an unwavering dedication to his craft. "I celebrate the fact that we've been handed matches that make life worth living," said Bielsa when Argentina were drawn in a group with England in 2002. 

But beyond tales of his eccentricity, Bielsa was and still is renowned for being a man of principle. After guiding Newell’s to a second Primera Division title in his first managerial role, the coach allowed his team to attend a friends’ wedding on the condition they were home by one o'clock because of an upcoming cup match. When he discovered that several players stayed out until the morning Bielsa asked the club to fine them for indiscipline, and following the board’s refusal he promptly resigned. Two years, two titles and a Copa Libertadores runners-up medal; it ended in the blink of an eye.

Despite leading Chile out of the international wilderness and to the second round of the 2010 World Cup, Bielsa's principles again paved the way for his premature departure. The election of businessman, Jorge Segovia, as the new president of the Chilean FA saw two polar visions on the national set-up collide and Bielsa, true to form, followed up the threat of his resignation. Protests and petitions followed but the campaign to keep the Argentine ended in vain before he returned to Europe with Athletic Bilbao.

That Bielsa remains resolute to his moral code is often overlooked for entertaining stories that preserve his 'El Loco' persona. Athletic forward Iker Muniain has claimed that his coach is "madder" than he is depicted by the media and Bielsa certainly pandered to his nickname amid an altercation with a construction worker at the club's training base in the summer. But there was reason behind his anger. "The condition of Lezama is an insult to the players and I am responsible for them," Bielsa explained. "I was indignant because that was not recognised and began to say offensive things. I don't respect him because he did a bad job." If something is worth doing, it's worth doing well. Athletic's failure to support their coach very nearly ensured another resignation.

Perhaps nothing better captures the fascination with Bielsa's character - the obsession over obsession - than a brief press conference exchange, recounted by Spanish football writer Sid Lowe, following a 2-2 draw between Athletic and Villarreal last season. El Loco had been in a particularly fraught mood throughout the match, pacing the touchline unremittingly and stopping only to crouch on his haunches; a familiar sight. One journalist had noticed that every time Villarreal attacked, Bielsa took exactly thirteen steps across his technical area. Was it superstition or mere coincidence, he asked. "What is coincidence, is that when there's such a nice game going on, someone spends time counting my paces," answered Bielsa. The journalist had been too preoccupied with the ringmaster to enjoy the show.

For all Bielsa's achievements in captivating football's diverse audience, and the admiration he has earned from his colleagues, he has always been revered with caution and curiosity. Tales of his tender nature have revealed his warmth and generosity, such as the time he readily relinquished tickets to a Copa Libertadores match to two penniless children before heading home to watch the game on TV. But how can even the most committed of football fans relate to a man known to sit in solitude at the training ground, analysing video footage in unparalleled, perhaps even unnecessary detail until the early hours? "Do you know that I die after every defeat?" Bielsa once said. "The next week is hell. I cannot play with my daughter or eat with my friends, it is as if I do not deserve those everyday joys."

Bolaño would have known how he feels. 'About happiness he said not a word,' the author described one of his many colourful characters. 'I suppose because he considered it something strictly private and perhaps, how shall I say, treacherous or elusive.'

Whether Bielsa appreciates his indelible impression is unknown and unlikely. He has noted that "a man with new ideas is mad until he succeeds", but how should we define success in a game of few tangible rewards? No, Bielsa's trophy is his madness, which is madder than that of any other and yet barely madness at all.

Follow Matthew on Twitter @MatthewStanger.