After getting knocked down early, Naoya Inoue overpowers Ramon Cardenas and earns a TKO win in the eighth round to retain his undisputed junior featherweight championship. But Inoue shook off the cobwebs and methodically went to work, using a stiff jab to set up a body assault that took some steam out of Cardenas' punches. It got loose in the second round. Both fighters' punches landed with an audible thump that drew a rise from the 8,474 fans inside the arena. Naoya Inoue celebrates after defeating Ramon Cardenas in Sunday night's junior featherweight title boxing.