Ivan Redkach (17-0, 13 KOs) scored a sixth-round stoppage of Yakubu Amidu (21-5-2, 19 KOs) at the Morongo Casino in Cabazon, California.
The scheduled 10-round Lightweight fight was the main event of a card promoted by Di Bella Entertainment and which was televised by Showtime Sports in the U.S.
Redkach, 28, of Shostka, Ukraine, recently moved to the training camp of Robert Garcia, and showed that he has improved since the change.
Redkach, instead of throwing an unnecessary number of punches, calmly took his time between powerful combinations that were thrown after a jab.
The jab played an important part in Round 5 when Amidu was dropped by a one-two combination and then again by a powerful flurry.
Amidu refused to continue on his stool before the sixth round.
In the co-main event, Alantez Fox (14-0-1, 4 KOs) scored a majority decision win over Patrick Day (9-1-1, 5 KOs) in a very close eight-round Light Middleweight fight.
Fox won with scores with 80-72 and 78-84 with one judge scoring the fight a 76-76 draw.