The favoritism in this thread is disappointing.
Simple Elesis tactic:
3 bars of mp are needed. If you manage to catch an opponent in the three pokes of Mega Slash, simply charge up the rest of your MP and let loose a sonic wave before the last blow of Mega Slash.
Air Spiral is a bit too situational for PvP anyway.
Kudaranai: I was on the subway and this man just PEED