Board Thread:General Discussion/@comment-13237238-20130803060401/@comment-8986886-20130805180429

Sternritter M wrote: I rather think he used Kendo just to kill off Nnoitra quickly. He was already annoyed because Nnoitra refused to accept losing without getting killed, so he dealt the final blow with Kendo to make sure he died and stopped being annoying :P

If you watch from 8min into ep202, after Nnoitra's attempt at decapitating him, you'll find that Kenpachi fears he might die if they keep fighting much longer. Therefore he decides to use his strongest attack, to end the fight in a single blow.

The final blow that you're referring to, is actually dealt after Nnoitra survives Kenpachi's Kendo attack.