Referee Clos Gomez had to halt the game on the half-hour mark as a section of the Gijon fans hurled racist abuse at the 22-year-old.
Sporting Gijon players urged the fans to stop the abuse and there was also a stadium anouncement pleading with the fans to stop.
Williams became the first black player to score for Bilbao in 2014 and also has one cap for the Spanish national team.
This is not the first time that Gijon fans have been guily of racist and abusive chanting. Back in 2008, the club received a €3,000 fine for racially abusing then-Getafe player Joffre Guerron.
Sporting Gijon won the game 2-1, thanks to a winning goal from Victor Rodriguez.