The fiend who brutalized a woman in Queens — beating her so badly she was hospitalized and unable to tell cops what happened to her — was arrested Tuesday morning, cops said.

Ronald Williams, 21, was picked up at a motel in South Carolina and was being brought back to New York on a probation violation, Chief of Detectives Dermot Shea said at a crime briefing at NYPD headquarters in Manhattan.

“Just hours ago in Columbia, South Carolina, we apprehended and are in the process of bringing back in the individual that was involved in that horrific assault in the 107 precinct last week,” Shea said, after reporting he had “good news” for Queens.

Cops had identified Williams as the brute who randomly attacked the 52-year-old mom after she dropped her child off at school on April 30. The attack happened around 7:45 a.m. in front of a residential building on 72nd Road near Kissena Boulevard.

The building’s superintendent found the woman unconscious and covered in blood with her pants pulled down at the bottom of an outside stairwell. Police sources said she had been sexually assaulted and that her facial injuries were so bad she couldn’t talk to them.

Cops had offered a $10,000 reward for information about the attack.