By Keith Idec

PHILADELPHIA – Doudou Ngumbu moved Saturday night until he couldn’t move anymore.

The light heavyweight contender from Congo suffered an apparent right Achilles’ tendon injury, which ended his scheduled 12-round light heavyweight title fight against champion Oleksandr Gvozdyk. After conferring with his corner men, Ngumbu determined he couldn’t continue and their ESPN main event was stopped 58 seconds into the fifth round at 2300 Arena.

Ukraine’s Gvozdyk (17-0, 14 KOs) was declared a technical-knockout winner because Ngumbu suffered a prohibitive injury. Gvozdyk was listed as a 100-1 favorite by numerous Internet sports books over the smaller Ngumbu (38-9, 14 KOs).

Gvozdyk defended the WBC title he won from Adonis Stevenson for the first time. The 31-year-old Gvozdyk knocked out Stevenson in the 11th round of their December 1 bout in Quebec City, Canada, to take that title.

Stevenson was placed in a medically induced coma due to the brain damage he suffered during that defeat. He since has begun a rehabilitation program in Quebec.

The 38-year-old Ngumbu entered Saturday’s fight with eight losses, but he had lost by knockout just once in his 12-year pro career. That defeat, a fifth-round stoppage, came against France’s Nadjib Mohammedi in June 2015.

In the fifth round Saturday night, Gvozdyk’s pressure kept Ngumbu on his back foot, right up until he took a knee because he couldn’t put his full weight on his right leg.

Gvozdyk caught Ngumbu with a flush left hook late in the fourth round. Ngumbu mocked Gvozdyk after taking that shot, but he spent much of the remainder of that round moving away from the champion.

Ngumbu had some success in the third round, when he landed left hooks, right hands and often kept out of Gvozdyk’s punching range.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.