A 22-year-old charged with stabbing a teen in the stomach outside a Brooklyn school was coming to the rescue of a neighbor who was being beaten with a baseball bat, his lawyer said Wednesday.

Victor Nunez, who was arraigned on attempted murder and a slew of other charges in Brooklyn Criminal Court, was merely a “third party” in the scuffle Tuesday that broke out outside Bushwick High School, attorney Marva Brown said.

She said Nunez was trying to help his 15-year-old special needs neighbor from being pummeled and didn’t stab the 16-year-old boy.

But prosecutors alleged Nunez was caught on video running from the group and ditching the knife in a flower box before ducking into a laundromat.

The victim, who just celebrated his birthday, is in stable condition.

Nunez, who has no criminal record, and the victim do not know each other, prosecutors said.

He was held on $100,000 bail.