DENISE Castle was forced to retire from her WBC World Silver Belt title bout with Sana Hazuki after a spirited display in Bangkok.

Veteran fighter Castle picked up a hematoma bump above her left eye in the fourth round, which ultimately restricted her vision and resulting in a retirement by round five.

Both fighters had no issues making weight for the atomweight fight, coming in at the scales at the same measurement of 46.2kg.

The contest started with both boxers looking to assert dominance via different methods, Castle opting for straight shots whilst her Japanese opponent Hazuki looked to string a combination of blows.

After the heavy bruise above her eye formed, Castle tried to put distance between herself and her opponent, whilst Hazuki maintained her combination-based approach.

By round five Castle’s left eye was all but shut, forcing her to retire on the stool and seeing Hazuki named champion.