Lyon, France (CNN) A few hours before Sunday's Women's World Cup final, John Ellis will seat himself at his organ and play "You'll Never Walk Alone ," Liverpool Football Club's stirring anthem. A Royal Marine commando who became a football coach, the 80-year-old is no vocalist, but nevertheless he will warmly sing the words and glance at a framed photograph of his daughter, Jill. It is a ritual the Englishman goes through every time the United States plays.

The picture John Ellis has above his organ is one taken during a jubilant time for the family and its adopted country, when Jill guided the United States to World Cup victory in 2015. There may be another photo to be put above the instrument Jill bought her father some years ago when he decided to learn to play because the USWNT head coach is a match away from retaining the title and making history.

"That song says it all," he tells CNN Sport over the phone from his Florida retirement home.

"When you're the head coach, you're the one on the line and that's why I sing that song to her, so she knows her mum, her dad, her brother are always here for her. I know it sounds stupid, but that's what I do.

"When you see your daughter out there, and the expectation and the pressure on her ... America is a wonderful country to live in, but don't lose. You've got to get it done."

Should the US triumph over the Netherlands in Lyon Sunday, the 52-year-old, described by her father as a strong but gentle soul, will become the first coach to win the biggest prize in women's football twice. In the history of the game, Vittorio Pozzo is the only coach to win two World Cup titles, leading Italy to victory in 1934 and 1938.

Her record is phenomenal: In 126 games as US head coach, she has won 101 and lost just seven. She has never lost a World Cup match. But like most of sport's elite coaches, Ellis divides opinion.

Her team has yet to lose a match in France; it recorded the biggest win in World Cup history by trouncing Thailand 13-0, and emerged from the group stages with a goal difference no team in the competition's history has achieved.

The USWNT has beaten an emerging force in Spain, and the No.3 and No. 4 team in the world in England and France respectively. Yet Ellis has still been criticized: for her substitutions, for being too defensive, for being too adventurous, for not being a true leader.

"When you take these big jobs, you understand that you have to be able to deal with that side of it," says her father, himself a former USWNT assistant coach. "Reading the newspapers, some people just don't like her, but the ironic thing is they don't know her."

Ellis celebrates with goalkeeper Alyssa Naeher after the semifinal against England.

A football awakening

England in the 1970s was not a country where young girls could harbor ambitions of becoming footballers. It was only in 1971 that the English Football Association ended the decree which banned women's matches from being played on the grounds of its member clubs.

Eager to encourage his daughter's enthusiasm for sport but knowing that there was no future in football for girls in his homeland, John Ellis would take her to a running track near the family's home in Portsmouth, a port city on the English south coast.

Often, he would stand near the bend before the home straight and watch Jill grit her teeth as she sprinted by.

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"I could tell she had this spirit," he says, "this drive to win. That's when I first saw it in her, on the running track. She was a little girl and I never tried to develop it. I've never tried to develop her. These things just came together."

An invitation for John Ellis to coach Annandale Boys Club in Virginia resulted in the family moving to America in 1981, which proved to be Jill's soccer awakening.

The lifelong Manchester United fan had grown up playing soccer on the streets with her brother and his friends, but had never been part of a team. That changed when the then-teenager joined Braddock Road Bluebells.

"There was just something about soccer," Ellis has said. "I don't think I would have had that opportunity until a lot later in England, and I probably wouldn't have pursued a career."

Meanwhile, at the family home, Jill was surrounded by soccer. With her father having set up a soccer academy, she would absorb information almost through osmosis. Former English professionals would visit the home and she would regularly attend her dad's training camps.

"There were no American coaches who knew anything about soccer back in the 1980s, so I'd bring in coaches from Britain, like Alan Kelly, a former goalkeeper who coached the Republic of Ireland, and those players used to live in my house, Jill was around them and they were like uncles," John Ellis, credited by his daughter for helping her learn how to "connect with people," says.

But soccer was still not a serious career option for the shy but determined kid who would become the first member of her family to attend university.

Turning her back on a lucrative career

The 1980s is nearing conclusion and a 23-year-old Jill Ellis has an undergraduate degree in English from the College of William & Mary, a master's degree in technical communications from North Carolina State and has chosen to earn a living in corporate America, but it is a grind.

Not even the annual wage of $30,000 is succor for the daily monotony of working alone writing manuals for a telecommunications company in North Carolina.

"I thought she was going to go on and make a million," says John Ellis, "but one day I'm talking to her and she says, 'you know dad, I just sit in a fricking cubicle all day and all you've got is the computer and I hate that.'"

A call from April Heinrichs, assistant coach at William and Mary where Ellis had earned third-team All-America status, was a turning point. Heinrichs, mentored by John Ellis at his academy, had become head coach at the University of Maryland and wanted Jill to be her assistant. But there was a snag: there was little money to be made.

She turned to her father for guidance, as she has throughout her career, and the man who knew how short life could be because of his time in the Navy told his daughter to follower her dreams.

Breaking out into a chuckle, John Ellis remembers: "The soccer job was going to be $6,000 a year. My wife says, 'you've got to be kidding me,' you've got all this education and you want to go to a job for $8,000 a year?'

"But money doesn't make anyone happy. It's what you achieve and the people you meet."

Ellis was named the 2015 FIFA World Coach of the Year.

Jill made a leap of faith thanks to her optimistic dad, but not even he could have imagined what she would go on to accomplish in the sport she fell in love with because of him.

"How can you ever see anything like that happening? You can't," he says.

Heinrichs and Ellis coached at Maryland for three seasons before moving to the University of Virginia in 1996. A year later, the University of Illinois came calling, offering Ellis an opportunity to build a women's soccer program from scratch.

Ellis had such an impact in Illinois -- the women's team reached the NCAA finals under her leadership -- UCLA offered her the job as head coach. She asked her father whether she was good enough, and once again her old man told her to live life on the edge.

Joe Mallia was part of Ellis' coaching team at UCLA for two years and remembers a passionate and competitive woman who instilled in the students the strength to persevere through difficult times.

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"She was great at getting the most out of players," he tells CNN Sport.

"Pushing them past boundaries that I did not think players could possibly be pushed beyond. Sometimes you push a kid too hard, but plenty of times you get it right and you get a player to realize they can do more than they think they can do.

"Players really appreciated Jill's passion for the game, and passion to make them better and drive to make them better. Not necessarily everyone benefited from that, but there were players she coached at the collegiate level who went on to play at the World Cup.

"People can criticize her all they want but, at the end of the day, her teams have won."

Over 11 seasons, she led the Bruins to eight NCAA Final Fours. By the 2011 World Cup, Ellis had coached the USWNT's Under-20s and Under-21s and assisted Pia Sundhage with the senior team for the 2008 Olympics.

"She just seems to have that in her blood," says John Ellis, explaining his daughter's remarkable ability to win.

Educated, courageous, dividing opinion

There are those who argue that anyone would be able to guide a squad as gifted as the US to glory, but football history is filled with tales of underachieving talented teams.

Within a year of becoming US head coach, America's English-born coach won the World Cup, but there were those who argued that the tactical switch of moving Carli Lloyd further up the pitch -- which would prove to be a defining one when she scored a hat-trick in the final -- came by accident because of suspensions to Megan Rapinoe and Lauren Holiday.

The US soccer team celebrates its 2015 Women's World Cup victory with a ticker-tape parade in New York City.

The following year was a disastrous one, as the US was knocked out in the Olympic quarterfinals on penalties after being shackled for 120 minutes by Sweden.

According to Sports Illustrated, in 2017 a group of veteran players told then-federation president Sunil Gulati that they wanted a new coach unless their concerns with the direction of the team were addressed. But Ellis kept her job, was given time and consequently shifted the direction of the team and put long-term plans in place.

Gulati, speaking to CNN Sport at an Equal Playing Field summit in France, said that he stuck with the head coach he had appointed because of her vision for the program.

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"Jill's track record is terrific so a penalty loss in the quarterfinals of the Olympics doesn't mean anything is going wrong," says Gulati, now a member of the FIFA Council.

"You lose a couple of games, players are unhappy, those things are all part of the process and I've had confidence in Jill throughout and, frankly, she's completely justified that confidence that US Soccer has had in her."

For a coach whose job would be on the line were she to oversee just a couple of consecutive defeats, Ellis has made courageous decisions over the years: adjusting her formation to a more attacking 4-4-3; picking players in positions they were initially unfamiliar with -- she made Julie Ertz, a central defender for her club, a holding midfielder, converted Crystal Dunn to a marauding full-back, and turned Kelley O'Hara from an attacking player into a defender -- and gave young talents such as Mal Pugh and Rose Lavelle a chance.

"When I was newer on the team, I remember Jill saying she wanted to bring really high-level soccer to the United States so our fans, and America in general, could see women playing soccer at such a high level," midfielder Sam Mewis has said.

"I credit Jill a lot for wanting to do that and then actually making it happen. She's pushed this team a lot and she has really high expectations for us and that's an exciting thing for her and for the team."

Former international Abby Wambach has described this as the greatest USWNT team in history, while England boss Phil Neville said Ellis was the best coach at the World Cup. Not everyone sees it that way, but it is not a head coach's job to be universally liked.

"She's not the leader I wish her to be," Hope Solo has said in her role as a pundit for the BBC in this tournament -- but the former US goalkeeper's criticisms of Ellis may not come as a surprise. Ellis was head coach when US Soccer terminated Solo's contract after she called Sweden's players "cowards" for their defensive tactics at the Olympics.

"She relies heavily on her assistant coaches," Solo has said, but so do many great managers. Liverpool boss Jürgen Klopp has, in the past, said that accepting his personal limitations and surrounding himself with people with "better knowledge in different departments" has been key to his success.

"She gets good staff and good coaches and she gets staff that are knowledgeable and trustworthy and get the job done," says John Ellis, who believes that it is his daughter's inquisitiveness which drives her to further success. "She has this instinct to be a motivator and inspire and that's why she's a winner."

Ellis is one of nine female head coaches at France 2019.

The USWNT squad is made up of highly-educated players. Of the 23-player squad, 21 have University degrees. Stanford graduate Tierna Davidson intended to become an astronaut, for example, before soccer took the 20-year-old onto a different trajectory.

"You can't bulls*it them," says John Ellis of the team. "You've got to be accurate, you've got to be detailed because they have the ability to really understand and to challenge you.

"That puts a demand on Jillian because she and her staff have to have really good management skills. It's not easy. You've got to have personality and a humor that can deal with that."

With hope in your heart ...

On Sunday, John Ellis will have planted American flags in flower pots dotted around the front lawn and passers-by will not fail to notice a 2015 World Cup banner hanging in the garden.

His son, Paul, his grandchildren and Ellis' wife Betsy will be in Lyon, watching the match unfold at the city's Olympic Stadium. But John will be in Florida, wearing the lucky red shirt he has owned for over a decade, and watching the team his daughter has assembled on television with his wife Margaret. He knows it will be an exhausting experience because he has gone through it over a hundred times.

"When she wins a game, we think, 'Thank God for that, she'll keep her job.' America is so win, win orientated, and if you don't win they'll fire you and that's the way of life and she understands that," he says.

The records broken along the way to the final would be no balm should the US lose to a Netherlands team competing in its first World Cup final. Anything other than victory would be a disaster, and the finger of blame would no doubt point in the direction of the head coach.

But football is a sport of extremes. While disaster is a possibility, so too is triumph and greatness.

Her dad will have hope in his heart. "Sometimes in life the stars just line up and when that happens it happens," he says.