The shout comes from Cristiano Ronaldo's Siu celebration, which he popularised during his time at Real Madrid in the mid 2010s after scoring goals. Derived from the Spanish word si meaning yes, the cry spread through stadium broadcasts, FIFA games and social media clips. Fans began stretching the vowel into suuuuuu for remixes and soundboards, turning a post goal ritual performed by crowds around the world into a reusable audio meme for any victory, large or small.