American heavyweight Deontay Wilder is now 30-0 with 30 knockouts after knocking out Nicolai Firtha in the fourth round of their fight Saturday at Boardwalk Hall in Atlantic City (on Showtime).

Wilder, who is 6-foot-7, connected with a mean right hand to the head of Firtha, who dropped to the canvas. When referee Lindsey Page saw Firtha could not push himself off the canvas, he waved off the bout without reaching the count of 10.

Wilder, of Tuscaloosa, Ala., is 28. Firtha, of Akron, Ohio, is 34. He is 21-11-1.

The bout was underneath the light heavyweight title fight between Bernard Hopkins and Karo Murat.