PORTLAND — The estate of a Westbrook man who died after he was punched in the face and hit his head on the bricks of Monument Square is suing his attacker and the bar the attacker patronized before their brief encounter.

Eric Benson’s estate is suing William Googins of Gray and 42 Wharf Enterprises, which operates the Oasis, seeking unspecified damages for wrongful death and conscious pain and suffering.

The complaint filed last week in Cumberland County Superior Court accuses both defendants of negligence and recklessness — Googins for the assault and the Oasis for allegedly serving alcohol to him even though he was underage and visibly intoxicated.

The three-page complaint says Googins was still drunk from the alcohol he was served at the Oasis, but it does not provide detailed allegations of what happened at the bar in the Old Port before the assault.

Benson was 24 and about to graduate from the University of Maine at Farmington. He and a female friend crossed paths with Googins and two of his friends in Monument Square in the early morning of March 23, 2010. Googins’ group made sexual advances toward the woman.

After Benson told Googins to leave, Googins hit Benson in the face. Benson fell and hit his head, and Googins’ group ran away.

Benson died later that morning at Maine Medical Center despite the efforts of witnesses who tried to administer CPR, rescue workers and surgeons.

Googins turned himself in the next day after police made details of the attack public public and a man from Googins’ group contacted them.

Googins is now 22 and an inmate in the Maine Correctional Center in Windham. He pleaded guilty to aggravated assault in an agreement that led to the dismissal of the initial manslaughter charge against him. He was sentenced to 10 years in prison, with all but two years suspended.

He is expected to be released in August, then serve three years of probation, which includes a community service requirement of 400 hours and a ban on drug and alcohol use.

Googins did not respond Monday to an interview request sent through the correctional center. He has said that he did not know his punch could so seriously injure Benson.

Wendy Benson, the victim’s mother and the personal representative of his estate, could not be reached Monday. Her lawyer, William Robitzek, did not return calls seeking comment.

James Cloutier, the lawyer who handles corporate matters for the Oasis, said the business has “very rigorous procedures” to ensure that there’s little possibility of liquor law violations. He would not elaborate on the procedures.

“The company evaluated the circumstances and does not believe it has a liability for the very unfortunate circumstances that led to this young man’s death,” Cloutier said Monday.

John Whitman, the lawyer representing the business in the lawsuit, said he and his client sympathize deeply with Benson’s family. “The facts will show, however, that this tragedy was brought about by William Googins and not the Oasis,” he said.