The victim and a few of his friends were hanging out around 3:45 a.m. on the private patio of his residence on Ocean Front Walk, just north of Belmont Park, when two men in their early 20s walked in and asked to join them, San Diego police Officer Dan Lasher said.
As the resident was asking the uninvited guests to leave, one offered a handshake, Lasher said. However, the suspect used the usually friendly gesture to pull the man close and stab him four times in his wrist, shoulder and back, according to the officer.
The assailant and his companion then walked away on Ocean Front Walk, Lasher said.
The victim was taken to a hospital to be treated for his injuries, which Lasher said were not life-threatening.
Police described the attacker as white and in his 20s. He was wearing a baseball cap and a gold jacket.