It's a good thing Justin Chentnik isn't modest.

If he were, his friend would be out a car, and he'd be out a good story.

Chentnik, a sous chef at a retirement home, says he was completely naked in bed about 4 a.m. Friday when Skip, the mini goldendoodle he was watching for friends, started barking up a storm. His friend and roommate, Laura Nelson, swore someone was in the house, but he told her to go back to bed.

Then she yelled that someone was stealing her car and threw a glass of water in his face to wake him up, Chentnik said.

Chentnik jumped out of bed and saw the reverse lights on Nelson's 2003 Mitsubishi Montero. Indifferent to his lack of clothing, he ran from his house in the 2800 block of Seventh Street in Boulder, opened the passenger-side door of the moving car and took the keys out of the car. Nelson called police.

The man who had tried to drive away in the car jumped out, Chentnik said, and the two men began struggling in the street. Chentnik grabbed the man by his shirt and pulled him onto the lawn.

“I was naked, and I thought, ‘If I'm going down, I better not do it in the street,'” he said.

The man had a full wine bottle — a Louis Jadot Pinot Noir — and hit Chentnik on the head with it, he said. Chentnik then grabbed the bottle and hit the man in the face.

When police arrived five minutes later, they found Chentnik straddling the man's chest in his front yard.

“I needed Skip to bring me my underwear,” he said.

Once police sorted out which one of them was the suspect, Chentnik learned Nelson had been right — there had been someone in the house. The man had broken the screen door, unlocked it from the inside and stolen the car keys from their house, Chentnik alleged.

Police arrested Benjamin Smith III, 24, on suspicion of charges including burglary, second-degree assault, second-degree aggravated motor vehicle theft, DUI and driving with a revoked license. Smith was on probation from a previous DUI.

According to the police report -- which did not mention that Chentnik was nude -- Smith said he went to Chentnik's and Nelson's house because he thought they might want to party. When they didn't answer, he let himself into the house, hung out and played with the dog. Then he took the car keys to listen to music in the car.

Chentnik said Smith is the son of a couple who lives down the street.