Quote Originally Posted by Xurts
The fight was real. After Safer Sephiroth had been defeated, Sephiroth was still not completely destroyed. He attempted to control Cloud like he had done in the past so he could block Holy.

That battle was a battle of wills, and Cloud won. Sephiroth failed to control him. That's why he never moved from where he was standing, he fought Sephiroth mentally.
So it was a mental fight, not a real fight.