Cops are on the hunt for a maniac who sucker-punched a man leaving Yankee Stadium after a game in August — an attack that left the victim semi-conscious, police said Friday.

The brute randomly socked the 20-year-old victim in the head outside the Bronx stadium on Aug. 19 at about 10 p.m., police said Friday.

The victim fell to the ground from the blow and smacked his head against the ground, cops said.

He was taken to Lincoln Medical Center in critical, but stable condition in a semi-conscious state, police said.

The suspect fled the scene on foot.

The Yankees hosted the Minnesota Twins that night and notched a 7-5 win.

An NYPD spokesperson could not specify if the victim was at the stadium as a fan, or if he worked there.