Watch: Hernandez lays Dariush out 42 seconds into short-notice UFC debut

Welcome to the big show, Alexander Hernandez.

The unheralded newcomer thunderously announced his arrival at UFC 222 on Saturday, flooring fellow lightweight Beneil Dariush with a left hand that led to a 42-second KO in Las Vegas - just over a week after agreeing to fill in for an injured Bobby Green.

The emphatic finish extended the 25-year-old's win streak to seven, with five of those victories coming inside the distance. Dariush, on the other hand, is now winless in three, a pair of KO losses to Hernandez and Edson Barboza sandwiching a majority draw opposite Evan Dunham at UFC 216.