Well, it's been a while, but from what I remember you have to let him track your sword with his hand, hold it in one position until he stops, and before he's able to grab it you have to quickly hit from the opposite direction. I fought him numerous times in boss rush mode and was able to defeat him easily, even in his final incarnation.
There is one exception though. Can someone please explain exactly how they fought Ghirahim? The first time took me 45 minutes, no joke, and the second time wasn't much quicker. All that seems to happen is that his hand follows my sword and he catches it. Sometimes, by pure fluke, I get a couple of hits in, but that's it.
Edited by Kay at 13:00:58 07-08-2012