A 31-year-old Marine vet who served five years in Iraq and Afghanistan used his best weapon to stop a would be rapist this morning in Queens — a deep jarhead scream.

Brian Teichman was dropping off his 2-year-old daughter at the babysitter’s house on the shoulder road of the Cross Island Parkway in Whitestone when he spotted a man forcing an Asian woman over a guardrail across the street and into a deserted, wooded area.

“It didn’t seem right. Once I saw him launch her over the guard rail I knew something was wrong,” said Teichman.

“I am an ex-Marine, so I’m not scared of conflict. I looked down and I saw him straddling her and he had his hand over her mouth and he was trying to rip her shirt off,” he recalled of the frightening 9 a.m. incident.

“My thought was ‘scream first, if he runs you don’t need to worry if he has a gun or a knife.

“In the deepest scream I could, I said, ‘Hey get the f—k off of her !’ He looked up at me and then ran down the hill, toward the west bound shoulder of the Parkway, “Teichman said.

Teichman said he ran over to the hysterical woman and picked her up.

“She was in tears. She was a small frail Korean woman. She was crying and distraught, she couldn’t walk and I had to pick her up and get her back over the guardrail. That’s when he and babysitter Dawn Ottaviano, 45, called police.

The suspect, who appeared to be in his 50’s, clean cut, 5’11″ and 200 pounds wearing a tan baseball cap was being sought by police.

“In hindsight I feel like I didn’t do my job until they catch him,” said Teichman, who is now a student at Nassau Community College and was supposed to take a physics test.

“But if I didn’t do that probably no one would have heard her scream,” he said.