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 fatally jumped 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.”

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

He had taken his wife to the concert to celebrate their 25th wedding anniversary, which was Tuesday, kin have said.

The Post exclusively viewed video footage showing Kueker jumping head-first over the barrier, with the witness Tuesday describing hearing a sudden loud bang seconds later, followed by the stricken screams of bystanders.

The witness said Kueker jumped during intermission, when about 25% to 50% of people were in their seats.

Other video footage captured the chilling moments right after the horror when bystanders and emergency personnel huddled around Kueker, trying desperately to save his life, to no avail.

Kueker, a dad of two from Niantic, was director of operations for the energy management company Smartcon Solutions, according to his LinkedIn account.

The city medical examiner’s office said an investigation into the cause of death is not complete.