The bantamweight bout was stopped in the second round after the American kicked an opponent in the head and then finished off.
Before the start of the fight, Sandhagen was ranked fourth in the list of the best fighters in this division, and Moraes was the first.
The UFC bantamweight champion is Russian Peter Yan, who does not yet have an official opponent for the next fight.
Earlier it was reported that Ulanbekov defeated Silva in his debut fight in the UFC.