The blaze broke out shortly before 6 p.m. at the building in the 1100 block of North San Fernando Road at Alice Street very close to the 110N to 5N freeway interchange.
ABC7 viewers who were at Saturday's game sent photos from their seats showing the smoke in the air. According to the Los Angeles Fire Department, the building was destroyed and is now "structurally unstable."
The two-story building on the southeast side wasn't damaged during the fire though investigators said this would remain an "active incident" into the night.
It took more than 100 firefighters to put out the blaze. No injuries were reported and the cause of the fire remains under investigation.