Two off-duty firefighters are credited for stopping the spread of a destructive fire at a Pacific Beach condo complex Thursday morning. The firefighters were near the complex on Diamond Street near Pacific Beach Community Park when the fire erupted inside a downstairs unit at about 4:30 a.m. They "heard the fire and ran for assistance and actually were able to close the front door of the unit that was on fire, which helped confine it to that unit and keep it from spreading to additional units," San Diego Fire-Rescue Battalion Chief Craig Newell said. When four fire engines and two dozen on-duty firefighters arrived to the scene, the off-duty firefighters had already pulled fire lines and evaluated the building's structure. The prep work helped SDFD get the blaze out within 30 minutes with only minor smoke spread to the upstairs units.