The man who allegedly fatally sucker-punched a stranger in Queens was arraigned on just an assault charge Tuesday after a count of criminally negligent homicide was dropped by prosecutors, officials said.

Matthew Smith, 42, who turned himself in at the 75th Precinct stationhouse in East New York on Monday, originally was slapped with both counts — but on Tuesday he faced only a charge of assault with intent to cause physical injury.

The attack on Gorman is colloquially known as a “one punch homicide.” In most instances, there is no proof of any felonious intent, according to the Queens DA’s office.

At most, a prosecutor can charge assault in the third degree, a misdemeanor, which requires only the intent to cause physical injury, the office noted, as it explained why the homicide charge was dropped before Smith’s court appearance.

Patrick Gorman was walking near Queens Boulevard and Main Street in Briarwood when he bumped into Smith’s 39-year-old girlfriend, Elena Makarova, just after midnight on June 26, police sources said.

“Excuse me,” said Gorman, 64, before Smith belted him in the face, sources said.

Surveillance video shows Smith punching Gorman, who is seen falling squarely on his back as the duo calmly amble off.

Gorman tried to get back on his feet, then collapsed. He was taken to Jamaica Hospital, where he died the next morning, police said.

The city medical examiner ruled Gorman’s death a homicide late last month.

Smith’s lawyer, Michael Wilson, defended his client at the arraignment.

“My client has only one prior conviction of which he received five years’ probation, which he completed to such satisfaction that he was granted early discharge,” he said.

“Also, your honor, he’s been charged with an ‘A misdemeanor.’ This is not a homicide. The people are alleging that a single punch killed this man? I don’t think they will be able to charge him with murder. We believe this case will remain assault in the third degree. The defendant has been accepted into the supervised release program and we ask that he’d be allowed to be participate in the supervised release program.”

On Sunday, Makarova, who has not been arrested, also came to her man’s defense on social media.

“Tmes and so relevant!!!,” she cryptically posted. “I love you hunny. Hold ur head! It’s so ignorant of people to jut read the papers and take it as if God talking!!! Nobody shows the footage where this man pushed me, curse me out, called matt n/$$@…I’m not feeding into this s—. All I can say is get ur facts straight!”

Smith was held on $10,000 bail, cash or bond. His next court date is set for Nov. 22.