The bullied Bronx teen charged with fatally stabbing a classmate and wounding another had a switchblade on him that day for “protection,” his lawyers claimed Friday.

Christopher Lynn painted client Abel Cedeno as the real victim of the 2017 attack at Urban Assembly School for Wildlife Conservation in East Tremont.

“Abel was the subject of the attack,” Lynn said in his opening arguments as Cedeno’s bench trial got underway in Bronx Supreme Court. “The sole purpose use of the knife was to protect himself from physical harm.”

Cedeno is charged with fatally stabbing Matthew McCree, 15, and slashing Ariane LaBoy, 16 — but claims the boys were bullying him.