A slow-moving street sweeper struck and killed a man near Barclays Center just hours after the Brooklyn Nets won a homecourt buzzer-beater on Friday night, cops said.

The man, whom police have not identified, fell onto Flatbush Avenue near Atlantic Avenue at 1 am — and was then hit by a sanitation vehicle, police said.

The driver, who was headed northbound on Flatbush Avenue, honked to warn the confused pedestrian — to no avail.

He was driving no faster than 30 miles per hour and was not charged with a crime, cops said.

The bizarre accident occurred two hours after a thrilling double-overtime Nets-versus-Detroit Pistons game ended, sending excited and tipsy fans into the street to celebrate.

It’s unclear if the man attended the game — but his death rocked sports fans and neighbors, who are still adjusting to the sometimes-rowdy new arena crowd.

“Everything is just crazy now. Your life can go so fast,” said neighbor Samantha Semidei, 25.