Williams Jr., who is of Ghanaian parentage, starred in Spain’s impressive win against England at the Olympic Stadium in Berlin.
The talented forward scored the opening goal of the game in the 47th minute after an assist from Yamal Lamine.
Later in the game, England drew level when Chelsea star Cole Palmer scored a screamer from outside the box after Jude Bellingham set him up in the 73rd minute.
While the game appeared to be heading for a draw, Mikel Oyarzabal won it for Spain in the 86th minute with a goal assisted by Marc Cucurella.
England also lost the 2020 European Cup final against Italy at Wembley, and its standout goalkeeper Jordan Pickford said the England players were "devastated" after Sunday's 2-1 defeat to Spain in the Euro 2024 final in Berlin.
Pickford, 30, was speaking to BBC Sport after manager Gareth Southgate had addressed his players in the dressing room.
"He [Southgate] just mentioned that was the 14th match we have had in the Euros and the first match we have lost in normal time," Pickford revealed. "We have been on a hell of a journey and we are devastated tonight - there is nothing more to say."
While the Spain players and management were celebrating a record fourth European title, England's search for a first Euros crown goes on.