Wait until his attention is diverted. Grab him and start stabbing him as well. --- I understand you have your pride...but I have my principles ! - Kenichi Sazh - Racist caricature and worst FF character ever. Don't agree ? Your problem.
As for beating the Griffin, take Phils advice and: http://www.youtube.com/watch?v=aib4TMTZyvE --- If there are females in this world, they lurk in the depths of my pants. Want to join them? Official Gaara of NUNSG boards. Official Xion of KHDDD boards.
Use fire. When your weapons get fire-enchanted by Alexandra - the manly mage with a girl's name - snipe the Griffin's wings. Or jump on it's back and attack the wings. You can't climb on the wings, but you can attack the wings at the joint on the back - the brown feathery part of the back.
Then when it's down, attack the head. --- You too....shall come to understand....Fear...as I do. PSN - Rockpopple