A Chicago man who became enraged at losing a video game and viciously beat a 4-year-old boy in 2012 has been sentenced to 20 years in prison, according to prosecutors.

Terrance Clay, 26, pleaded guilty Friday to two Class X felony counts of aggravated battery to a child for the attack that left the boy with permanent brain damage, according to a statement from the Cook County State’s Attorney’s office.

Prosecutors said Clay would regularly watch the boy while his mother worked an overnight shift at a restaurant. On Jan. 7, 2012, Clay was playing “NBA 2K12” until about 4 a.m. and losing badly as the boy slept nearby.

He became enraged at the game and “pulled the sleeping boy out of bed and slammed him to the floor. Clay then put on the victim’s children’s boxing gloves and began punching him in the head and abdomen,” prosecutors said.

The boy was taken to a hospital and diagnosed with “several subdural hematomas as well as internal injuries,” the statement said. He “lost some brain growth ability and will never reach his full cerebral capacity.”

Judge William Lacy sentenced Clay to 20 years and, by law, he must serve at least 85 percent of the sentence before being eligible for parole.