Santos tried to defend on the mat, but Hill landed elbows until referee Herb Dean stopped the fight.
But Hill has a ton of power in his hands, and the strategy was a smart one for Santos, who landed a career-high five takedowns.
Hill, 31, is 5-1 (1 NC) in the UFC with four KO/TKOs -- tied for the most in the UFC light heavyweight division since 2020.
UFC Fight Night: Santos vs.Also on the card Saturday night, Mohammed Usman knocked out Zac Pauga in the second round to win the heavyweight tournament of "The Ultimate Fighter 30" reality show