Three things. One, deflection also works with Biggoron's Sword. Two, he ment the ring of fire around the arena. Three, you repeat the strategy with the Master Sword, and when Zelda stuns Gannon, attack his nose and enjoy watching Link hack away at Gannon, then enjoy the ending.
P.S. If you played a song to Pieere that will be played with various instruments. If you didn't your Scarecrow's Song will be played. If you didn't do THAT either then that's too bad for you, because you don't get this last reward.
Mario, Mario, Mario! What happened to Mr. Andretti?