Chris Eubank Jr won his second professional fight with a points win over Doncaster's Jason Ball.
Eubank, 22, controlled the pace of the early rounds, landing a string of body blows, but was pegged back by a resurgent Ball, who finished well.
But the Brighton fighter, who spent four years in Las Vegas learning the art, was awarded a 58-56 victory.
"I did what I had to do and came away with the win. I only used my left hand," said Eubank Jr.
"In training a few days ago I jarred my right and knew I wasn't going to be able to use it tonight. But I'm not going to pull out of fights with injuries."
Eubank Senior, who supported his son from the front row, said: "For him to beat a fighter of his experience with only one hand is exceptional. I'm happy."
On the same bill, Kid Galahad beat Jason Booth for the vacant WBC Intercontinental super-bantamweight title.