Shuaibu Amodu, the only man to have qualified Nigeria for two World Cup finals, has died at the age of 58.
Amodu, who coached Nigeria on four different occasions, is thought to have passed away in his sleep in the Southern Nigerian city of Benin, after complaining of chest problems.
The death of the Nigeria Football Federation (NFF) Technical Director comes just days after former Nigeria coach and captain, Stephen Keshi, passed away aged 54 in the same city.
NFF president Amaju Pinnick said: "This is another tragedy too many. We are still talking about Keshi's death, and now Amodu is gone. I'm short of words."
Amodu, who first took charge of Nigeria at the age of 36, was approached to replace Sunday Oliseh in February but declined on health grounds, according to the country's football authority.
Oliseh who worked under Amodu as a player and coach Tweeted: "Waking up to another devastating horrible news: Amodu Shuaibu, former coach of Nigeria is proclaimed dead! First Keshi and now this. God help us!"
A NFF statement said: "Amodu's name was synonymous with the Super Eagles. You can't talk about the history of Super Eagles without Amodu getting prominent chapters.
"He qualified the Super Eagles for the FIFA World Cup in 2002 and 2010, but did not lead the team to the finals. He also qualified the Beach Soccer National Team for the 2006 FIFA Beach Soccer World Cup, but did not lead the team at the finals as he refused to travel to Brazil.
"As Technical Director he was known to be hypertensive, and had rejected taking over the Super Eagles coaching job in February on this ground."
Amodu first shot to prominence when he guided Nigerian side BCC Lions of Gboko to win the now-defunct African Cup Winners Cup in 1990.
His team reached the final of the same competition the following year but lost to Zambian side Power Dynamos 5-4 on aggregate in 1991.
Three years later Amodu replaced Dutchman Clemens Westerhof as Nigeria coach in 1994 and then led reigning African Champions to fourth place at the 1995 King Fahd Cup (now renamed Fifa Confederations Cup) before his exit later that year.
He returned to manage the team again from 1998-99, 2001-02 and 2008-2010.
He helped the country to qualify for the 2002 World Cup in Japan and South Korea and led them to a third-place finish in the 2002 Nations Cup.
Under his stewardship, Nigeria qualified for the 2010 World Cup in South Africa but Amodu was sacked despite the team's third-place finish at the 2010 Africa Cup of Nations in Angola.
It was the second time he had been removed from his post ahead of a World Cup finals tournament - Amodu was also fired ahead of the 2002 edition after Nigeria finished third at the 2002 Nations Cup in Mali.
Despite his remarkable achievements as Super Eagles coach, Amodu had a turbulent relationship with the fans and his employers, with critics constantly questioning the team's style of play, his tactics and key decisions.
The NFF named him as the National Technical Director in May 2013 but his appointment was only confirmed in October 2014.
Fiery, highly respected by his colleagues, passionate, conservative and a man who possessed strong knowledge of the game, Amodu was always outspoken.
In his last interview with BBC Sport in March, Amodu cited all the problems blighting Nigerian football and was keen to sit down with his employers to proffer solutions.
"I must confess that all is not well with Nigerian football in terms of structure and funding," he told BBC Sport.
"We really need to rejig the whole aspect of our football if we have to be serious and sustain development at a high level.
"I've been taking notes and these are some of the things I will bring up when I meet with the NFF."
Amodu at club level:
Amodu, who began his coaching career with BCC Lions and also handled rivals El-Kanemi Warriors, is the most decorated coach in Nigerian FA Cup history, having won it in 1989, 1992, 1993 and 1994.
He won the Nigeria League and Cup double in 1994, and won the Super Cup in 1989, 1993 and 1994.
He also managed South African giants Orlando Pirates between 1996 and 1997.