Complex sentence: However, Mormeck lost his WBA and WBC cruiserweight titles to O'Neil Bell in a classic by knockout in the 10th round on 7 January 2006, for the undisputed (WBA/WBC/IBF) cruiserweight championship.
Split into simpler sentences: However, Mormeck lost his WBA and WBC cruiserweight titles to O'Neil Bell in a classic match after getting knocked out in the 10th round. This bout, on 7 January 2006, was for the undisputed (WBA/WBC/IBF) cruiserweight championship.