Former Leeds United and Wales midfielder Yorath was a giant of the sport in Wales and a member of the exclusive club of footballers who have played for and managed their country.
He was also, famously, one penalty kick away from leading Wales to the 1994 World Cup finals.
Williams – who became a successor to Yorath as national captain and led Wales during their historic 2016 Euros campaign – said: “This is really sad news this morning.
“As a former Wales captain myself, I know he's such an icon in Welsh football.
“It's a huge, huge loss. He's one of those massive footballing names that you hear about when you get selected for Wales or when you're playing in Wales.”
Speaking on Sky Sports News, former Swansea City defender Williams said Yorath was always supportve of the players who followed in his footsteps.
He added: “You hear about these certain names. He's one of them. He's at the top of that list.
“You know that you've got to kind of live up to what they achieved before. And those are the people who have driven Welsh football forward.
“What we achieved, or for what the next Wales team achieves, it's all because of people like Terry Yorath.”
Yorath won 59 caps as a rugged midfielder between 1969 and 1981 before taking charge of the Wales national team in 1988.
Under Yorath, Wales reached their then-highest FIFA ranking of 27 in August 1993 and almost qualified for their second World Cup in the US in 1994.
Needing to beat Romania at home in their final qualifier, Wales were drawing 1-1 in the second half when Paul Bodin's penalty struck the crossbar.
Wales ended up losing 2-1 and, instead of being granted national hero status by taking the country to the World Cup, Yorath found himself out of work.
The Football Association of Wales did not renew Yorath’s contract and appointed Real Sociedad’s John Toshack as a part-time manager instead.
But Yorath’s former team-mate resigned after just one game with Welsh fans still upset at the dismissal of his predecessor.
Yorath was born in Cardiff in March 1950 and signed professional forms for Don Revie’s Leeds at the age of 17.
At first he found it difficult to find a place in a Leeds midfield featuring Billy Bremner and Johnny Giles, and was on the bench for the FA Cup final defeat to Sunderland in 1973.
That same year he did start in the European Cup Winners’ Cup final loss to AC Milan.
But Yorath was a key member of Leeds’ 1973-74 championship-winning team as England-bound Revie marked his final season at Elland Road by beating Liverpool to the title by five points.
The following season Yorath became the first Welshman to play in the European Cup final when Leeds lost 2-0 to Bayern Munich in Paris.
But Yorath, by now skipper of a Wales team which would reach the quarter-finals of Euro ‘76, would move on to Coventry for £125,000 in 1976.
He was captain of a Coventry team that spent an entire first division season in the top 10 - the Sky Blues eventually finishing seventh - before joining Tottenham for £300,000 in 1979.
Yorath wound his career down at Vancouver Whitecaps in Canada and at Bradford, where he became assistant manager to his former Leeds team-mate Trevor Cherry.
He was at Bradford in 1985 when 56 fans were killed by a fire at their Valley Parade home, Yorath himself injured when he was forced to jump out of a window after evacuating supporters from a bar.
After winning promotion at Swansea from the old fourth division, Yorath was appointed part-time manager of Wales.
He combined managerial roles at Swansea and Bradford with the national job before concentrating on Wales in 1991.
At the start of the 1992 World Cup campaign he suffered personal tragedy when his son Daniel died at the age of 15 from an undetected heart condition while playing football in the back garden.
The father of three other children, his daughter Gabby Logan became a well-known broadcaster and television presenter.
After World Cup heartbreak and his departure from Wales, Yorath managed Cardiff, the Lebanon national team, Sheffield Wednesday and Margate.
Yorath also had several coaching jobs elsewhere, but he never hit the heights that almost carried Wales to a World Cup on a tide of emotion.
As well as daughters Gabby and Louise and son Jordan, he is survived by his former wife Christine, who he divorced in 2007, and three grandchildren.
