Night crews would patrol the area all night to ensure the fire did not break away, he said.
"The crews who have been out there since 6am have done a fantastic job. They're starting to come in now and they're pretty exhausted but they've ensured we've kept on top of this one.
"It's still pretty windy out there, but with luck we've seen the worst of the weather today and conditions will allow us to begin beating this back."
Tomorrow, firefighters would aim to knock out any hot spots, Mr McNamara said.
"I think we've got this beast by the tail now, but next we have to kill it," he said.
An evacuation plan was in place for residents of the Waihopai Valley.
People living in the area have been advised to be extremely cautious about moving across any area that could be in the path of the fire.
Members of the public have been advised to stay away from the Waihopai Valley if possible.
Parsons Rd, at the intersection with State Highway 63, is closed.
Drivers in rural Marlborough are warned that smoke from the fire could restrict visibility, and to take extra care.