A horrified witness recounted in grisly detail to The Post on Tuesday how he was struck by tragic leaping MSG concertgoer Paul Kueker — and left “standing in blood.”

“His head was like a foot to the left of my shoes,” the traumatized man said of Kueker, a 51-year-old married dad of two from Connecticut who jumped to his death from a 150-foot-high balcony at the Manhattan venue during a Goose concert Saturday night, according to video.

“Within a few seconds, I was standing in blood,’’ the witness said.

“Wild,” said the man, who was struck on his leg. “That’s why I’m trying to figure out what hit me, and my friend was one seat further away and got hit by something, so I want to figure out what that was, too.”

Several other people also were hit by the falling man and suffered minor injuries, sources said.

Kueker “appeared intoxicated” and “under the influence’’ before he took the leap over the 4-foot-high glass barrier shortly before 10 p.m. the day before Father’s Day, law-enforcement sources have told The Post, quoting witnesses.