Last week it was Lomachenko, the three-division champion, who destroyed former lightweight titlist Anthony Crolla by one-sided, one-punch knockout in the fourth round.
The fight ended in the sixth round when Khan could not continue after after an accidental low blow in the main event of the first Top Rank Boxing on ESPN pay-per-view card.
There was good action in the fourth round when Khan (33-5, 20 KOs), 32, of England, finally began to land punches and also stood up to solid ones as well.
They exchanged many punches in the fifth round but Crawford (35-0, 26 KOs), 31, of Omaha, Nebraska, appeared to hurt Khan, who took the punch and shook his head - a sure sign he had felt the shot.
Early in the sixth round Crawford landed a left hand very low that clearly hurt Khan, who was given time to recover from referee David Fields.