Juan Carlos Osorio's door into football began with a window in Liverpool

On Sunday against Portugal, Osorio will manage his first official match in Europe. There is one household in Liverpool, England that will be cheering on the Mexican national team every step of the way in Russia at the 2017 Confederations Cup.

Tom McManus, his wife Mary and sons Peter and Thomas welcomed Mexico's manager Juan Carlos Osorio into their home back in 1997, when he was studying at John Moores University in the city. He became part of the family. Osorio's name has become synonymous with an intense obsession for the beautiful game but to understand how and why the former New York Red Bulls coach ended up renting the small room at the top of the stairs with barely enough room to "swing a cat" (as Tom describes it), you have to first understand its location.

The McManus family home is on Crown Road, about five miles from the city centre. Crucially, the upstairs front windows overlook Liverpool FC's Melwood training complex and is so close that a stray ball from first team training once smashed one of the windows of the house. When Osorio, a complete unknown in the football world at the time, arrived in the city to embark on his Science and Football degree, he was drawn to the road and the house, with his ultimate goal of being able to find a permanent place to watch and study Liverpool's training sessions.

"I needed to not only get my licenses, but I needed to improve as a trainer on the field. So, I needed to see how the professionals work," Osorio said of his decision to move to Liverpool in an interview with ESPN's John Sutcliffe. "So I decided to put all the resources together."

To chase his dream, Osorio sold the small gym he had, packed his bags, temporarily left his wife -- as well as the chance of becoming a U.S. citizen -- and headed to Liverpool.

After trying and failing to talk his way into Liverpool's training ground, Osorio scouted the area and found a hole in the wall along Crown Road. It was then that he knocked on the McManus family's door, initially to ask for some steps to enable him to look over the high wall and onto the training pitches. Mary answered and said she didn't have any, but was impressed by Osorio's politeness and went back out to offer him a table. Osorio returned the table and even cleaned it.

The next day Osorio, accompanied by his omnipresent notebook and pens, came back.

After a few days, Osorio asked to live at the house and although at first Mary declined, the family agreed that it would be a good idea after talking more with the now 56-year-old, though they struggle to put their finger on exactly why.

"There's something about him that you can't describe," said Peter, who works with the homeless at the Salvation Army. "He knocked one day to borrow a table to look over the wall and five days later he was living here."

The family members acknowledge that letting an unknown South American student live in their house was unusual to an outsider, but the jovial family of Everton fans were convinced by Osorio's tenacity and dedication to studying and making it in the game.

Osorio stayed in the McManus household for two years while he completed his degree and became an important person in their lives. When he came back to northwest England in 2001 to become the fitness coach (and later assistant) at Manchester City under Kevin Keegan, the former Atletico Nacional manager used to return with his wife and children for the traditional English Christmas dinner with the McManus family.

Stints in MLS with Chicago Fire and New York Red Bulls followed; then came his real breakthrough in Colombia with Once Caldas and then Atletico Nacional. From there, Osorio moved to Sao Paulo in Brazil before taking on the significant challenge of managing the Mexican national team, where he is proving successful so far.

"What he showed to me and I think to our two boys is that if you want to achieve anything in life, you've got to be single-minded and totally determined to go for it," said Tom, who works as a carpenter and joiner and plays music in his spare time.

"Nothing gets in his way. From the day we met him and found out what he was about, we knew he would be successful and he is and I think he can go further again."

All the family members talk of him being "football mad." Osorio took every opportunity to watch the game and immerse himself in the country's football culture. Over the wall at Liverpool, French manager Gerard Houllier and Roy Evans were, for a time, implementing something a little different, something that was shaking up the English game. Houllier's rotation policy at the club was heavily criticized but was something Osorio took on board and has since become known for.

"It was a particular case because there was like a joint coaching staff," Osorio recalled. "It was Roy Evans and Gerrard Houllier. And for me it worked perfectly because then you have the background of Evans, the direct type of football that I wanted to learn."

Osorio's days in Liverpool were regimented. He'd get up early, stretch for an extended period on the landing upstairs much to the amusement of Tom, who would comically mock his guest's regimen. Indeed Tom suggested the wiry Osorio should try his diet of fried chicken and burgers to put on some weight.

After his morning exercises, Osorio would head off to university, join discussions with peers, play football, train and then spend hours watching Liverpool over the wall, sometimes from his small bedroom looking out onto the training pitch and other times by peeking directly over the wall. Other times he'd watch Everton train. Wherever he was, he was always taking notes.

"He seemed to live by his watch," said Thomas, who works as a managing surveyor. "His day was planned and timed almost to the minute. I laugh if I try to explain it to people. There's a film with Denzel Washington, "The Equalizer," in which he goes round and he times everything: five minutes, two minutes ... that is very much Osorio."

It isn't difficult to see how the meticulous planning of a day would transfer over into Osorio's scrupulous attention to detail in preparing for games. At the weekend, Osorio would travel all over the country to watch matches, often without a ticket, and was even detained outside Old Trafford once for unknowingly purchasing a forged ticket, a story Peter recounts with a hearty laugh.

When Osorio was living in the house, the family didn't have the TV package showing Premier League matches and for many people in England, that means a trip to the pub. Tom liked to take Osorio to the local one, but the manager never drank alcohol and set himself up in the boozy environment to study whichever game happened to be on.

"He wasn't shy," said Peter, who was in his late teens when Osorio showed up at the McManus house. "He'd grab a chair and sit among a group of people he didn't know. If they were sitting in front of the TV, he'd have to be in the best spot. He'd put his rucksack down, have a glass of water, get his notepad out and would be furiously writing notes as he was watching the game."

Said younger brother Thomas: "He lived a very clean life but equally he appreciated that it was part of our culture. He'd be respectful but certainly wouldn't be drinking."

One of Thomas' other favorite Osorio stories is taking him to the local gym. Osorio used to accompany the brothers on occasion and quickly became known.

"While he was in the gym he used to always attract a hell of a lot of attention," Thomas said. "He'd go around the gym with his notebook, his pad and his watch and every single exercise was measured to a time to be recorded and to chart his progress accordingly. It didn't take too long for him to attract attention ... within three or four sessions he almost became his own celebrity within the gym."

For both of Tom and Mary's sons, Osorio became like an older brother. And when he was back in England with Manchester City, Peter remembers Osorio knocking on the door one evening to present him with the shirt that Tim Cahill -- an Everton legend and Peter's favourite player -- had worn earlier in the day in the match against Manchester City.

"Unique," said Peter, when asked to describe Osorio. "I've never met anyone like him before in my life. He's a very special person. ... To see someone that close, especially in the early part of the career [when he] put in so much hard work when there were no guarantees."

But aside from the football obsessive, the family say there is more to the man they simply call "Juan," who is currently guiding Mexico with ease to Russia 2018.

"For me, there are two sides to Juan Carlos Osorio," Thomas said. "There is the very clear, focused driven football man. But aside from that, which probably isn't seen as often, he's a good-natured family man who has a good heart and a good sense of humour. While he lived with us there was always that balance."

Tom wishes that Osorio could show his wicked humor more often in his work environment.

"If he could just show a little bit more of his great personality, people would warm to him a little more quickly," Tom said. "They'll warm to him from the results, because he's good, but that takes time."

The family lost touch with Osorio after he left Manchester City in 2005, but has followed him every step of his career over the other side of the Atlantic.

"It wasn't a surprise or something that upset us or offended us," Thomas said. "It was just that Juan Carlos Osorio had moved on to the next chapter of his football career. Football comes first."

The family were reunited with Osorio over a video call as part of this story and the current Mexico manager invited them to see El Tri play in the Confederations Cup or another game in the future. Unfortunately, Mary isn't keen on flying but is hoping to see him closer to home in the near future.

"He's just still Juan," Mary said. "We knew Juan would do great things. He's so committed to whatever he sets his mind to, so it's what we thought would happen. We didn't know it would be Mexico; we thought it'd be the Premier League. We thought he'd come back and knock on the door and say I've come back as a manager of one of our teams. We still hope."

If Osorio has a good run with Mexico in the Confederations Cup and then next summer at the World Cup, the thought of the McManus family driving to see Osorio manage a Premier League game wouldn't be beyond the realms of possibility.