The stabbing at Congress and Taylor streets was reported at 10:08 p.m. Wednesday, according to San Diego police Officer David Stafford.
Two men walked up to the victim and issued a gang challenge before one of them pulled out a knife or box cutter and stabbed the victim in his face, he said in a statement.
Paramedics took the victim to a local trauma center, Stafford said, adding that the wound was not life-threatening.
Police described the suspects as young Hispanic men, around 5 feet 9, last seen wearing white shirts and blue pants. They fled in a newer white Nissan sedan, Stafford said.
Gang detectives were investigating.