Referee Mickey Vann stepped in to end proceedings after one minute and 37 seconds of the round.
The victory was Khan's 19th in 20 fights and restored the 2004 Olympic silver medallist's reputation which had been so badly damaged by his 54-second loss to Colombia's Breidis Prescott in September.
That was the sixth time the 21-year-old had been knocked down and raised doubts over his ability to challenge for a major belt.
Earlier, Welshman Enzo Maccarinelli made an explosive heavyweight debut when a series of vicious body shots blasted Mathew Ellis into submission in the second round.
Maccarinelli's planned WBO world cruiserweight title clash with Francisco Alvarez fell through when the Puerto Rican failed a medical but Ellis stepped in on Friday.
Audley Harrison's world title aspirations were left in tatters after Belfast taxi driver Martin Rogan edged their heavyweight clash with a points decision over the 2000 Olympic gold medallist.