"I'm going away saddened by the draw and because I've suffered racist insults," Williams told Athletic's official media outlet after the game.
"It's something that nobody wants to here, and which is totally out of place.
"People have to come together and enjoy themselves, to help their team.
"It's a friendship sport, a team sport... and it's been a bit sad because these events shouldn't happen. They're out of place."
Williams was noticeably affected by the abuse coming from a small section of the stand, which caused him to publish a tweet regarding the matter.
"It is very sad that today we still experience scenes of racism in football," it read.
"We have to end it among EVERYONE. Thanks for your support."
Es muy triste que a día de hoy sigamos viviendo escenas de racismo en el fútbol. Tenemos que acabar con ello entre TODOS. Gracias por vuestro apoyo. #NOalRacismo#SayNoToRacismpic.twitter.com/3UauFEXjH4— IÑAKI WILLIAMS (@Williaaams45) January 25, 2020