Forty-year-old fighter Choi has claimed the title of featherweight prizefighter after winning the event in York on Saturday night.
The `Mongolian Warrior` defeated Lee Glover, George Jupp and Rhys Roberts on his way to winning the £32,000 prize.
Choi, a beaten semi-finalist in the super-featherweight division last year, firstly knocked out the previously unbeaten Glover in the quarter-finals.
Points victories over Jupp and Rhys Roberts then followed as the veteran fighter used all his experience on his way to securing a surprise victory.
"I used my experience and like a robot I just go on and on and on," Choi told Sky Sports after collecting his trophy. "Thanks to my fans, I love you all."