A Staten Island man threw his two young children from a second-floor window and into the arms of two neighbors after their home went up in flames early Thursday, witnesses and authorities said.

The massive fire tore through the two-family townhouse on Chestnut Avenue near White Plains Avenue at 1:05 a.m. and quickly spread to two neighboring homes — injuring 34 people, the FDNY said.

The father of two was trapped inside the burning building but was able to extend his arms out of a window, holding his son, believed to be about 3-years-old.

“He was screaming ‘catch my son! catch my son! and I tried to position myself and he dropped his son and I caught him,” Good Samaritan Anthony DiSimone,40, said.

DiSimone’s fiancé, Darleen Cerzosie,39, then caught the man’s daughter.

“He had his daughter in his hands and was leaning forward saying ‘please save my daughter! help me!’ I said ‘let her go. I’ll catch her,” Cerzosie said.

“I fell back with her in my arms. I couldn’t get up so they [emergency responders] took her,” she explained.

Cerzosie suffered a sprained arm from the rescue but was glad she was there to help.

“The little girl got up and gave me a hug. I melted. I said ‘I told you everything was going to be okay.’”

Eleven civilians were injured in the blaze along with 23 firefighters; all taken to area hospitals, the FDNY said.

The fire also badly damaged a car shop run by Tottenville resident Carl Johnson, who lost his home in Hurricane Sandy.

He found his shop in flames after hearing about the fire over the radio while driving to work.

“My heart sank,” he said. “I was shocked.”

Their injuries vary from minor to serious and all are considered non-life threatening, authorities said.

The raging inferno took more than 200 firefighters and seven hours to get under control with firefighters extinguishing all flames at 8:45 a.m., the FDNY said.

The cause of the fire is pending an investigation by the Fire Marshal.