Toronto, Canada – Khan, a teenage Olympic silver medalist in 2004 who turns 23 on Tuesday, flew out of his corner and landed a right-hand punch that floored number one contender Salita after 10 seconds.
Salita got up shakily and walked straight into another flurry of punches that earned him a standing count, managing to convince the referee he was fit to continue.
Khan wasted no time in finishing it off, however, connecting quickly again with more shots and forcing the referee to step in and stop the fight after one minute, 16 seconds.
Having turned professional in the wake of his Olympic final appearance, Khan's meteoric rise was put on hold when he was knocked out in 54 seconds by Colombian Breidis Prescott 15 months ago.
Saturday's devastating show underlined Khan's status and will bump up his box office potential in the United States.
"Very explosive. It was just what we asked for," the Briton told the BBC. "We had too much firepower for this guy. After the first shot I could see his legs buckling."
Khan thanked trainer Freddie Roach for helping get his career back on track.
"Freddie is like a father figure to me and just having him in the corner gives me so much confidence," he said.
"It was a blessing in disguise what happened to me against Prescott -- I've come back stronger and now I'm a world champion and a world champion defender."