After the match, in which Wales and the USA drew 1-1, the defender revealed that his grandfather had died the night before the game.
The 21-year-old Nottingham Forest player paid tribute to his grandfather on the pitch, when he told the camera, “That was for you, grandad”.
Williams said on Twitter: “Yesterday was the toughest news I’ve ever had to face and that was listening to my mum tell me my grandad passed away last night.
“To go from crying all day to starting in a World Cup game was extremely tough but I got through it from the support of my teammates and family.”
He added: “So I dedicate that game and an important point to him.”
— ITV Football (@itvfootball) November 21, 2022
On Instagram, Williams went on to say: “He’s been everywhere around the world to watch me play football from when I first started playing at Liverpool at six years old.
“He’d never tell me if I had a good game because he always said I have to get better and better each day and that’s why I am where I am now!
“So I dedicate this game all to him because I know he’s up there watching down on me very proudly.
“For everyone please cherish [what] you have with loved ones because you never know when it can get taken away from you.”
Yesterday was the toughest news I’ve ever had to face and that was listening to my mum tell me my grandad past away last night😓 to go from crying all day to start in a World Cup game was extremely tough but I got through it from the support of my team mates and family❤️🕊 pic.twitter.com/3pcxl0C3Qc
— Neco Williams (@necowilliams01) November 21, 2022
Wales competed against the USA in their first World Cup match in 64 years, ahead of their remaining group-stage matches against Iran and England.
The USA scored against Wales in the first half, but Gareth Bale scored an equaliser with a penalty kick.
Wales will play against Iran on Friday, November 25, at 10 am, and then against England on Tuesday, November 29, at 7 pm.