After winning 15 of his first 16 professional fights, Kassi faced his first tough opponent. He was set to face Kendrick Releford in
Hollywood Casino,
Bay St. Louis, Mississippi, on April 24, 2010. He eventually lost the fight via unanimous points decision, after 10 rounds. Three times, he fought American contender
Chris Arreola, on July 18, 2015, at
Don Haskins Center in
El Paso,
Texas. The fight aired on
PBC and
CBS. The fight resulted in a controversial draw; many, including ringside observers, such as analyst
Steve Farhood, believed that Kassi won the fight. After the controversy with Arreola, Kassi fought
Dominic Breazeale at the
Legacy Arena in
Birmingham, Alabama. He lost via another controversial points decision. Breazeale was given a unanimous decision win by judges. Most observers regarded the fight as a draw or close-run win for Kassi. Kassi was set to fight
Hughie Fury for the vacant
WBO Inter-Continental
heavyweight title at the
Copper Box Arena on April 30, 2016. Kassi lost the fight via technical decision. The bout went to the scorecards after seven rounds when Fury was left with a gash over his left eye because of an accidental clash of heads. Kassi pressured Fury throughout the fight, landing power shots on his head. Fury struggled to contain him until the fight was suspended. Kassi was set to face
Jarrell Miller on August 29, 2016, for the WBO-NABO heavyweight title. The fight took place in
Rhinos Stadium,
Rochester, and Kassi lost as he retired in the third round, citing hand injury. ==Professional boxing record==