Instructions
Attack Gaara using Naruto's move in which he goes under the ground and pops up under his opponent. This move will break through Gaara's defense enough to harm him.
Power up your Chakra as you fight. You'll need it to deliver the final blow. Shake the Wii-mote while you play to power up Naruto's Chakra. When Naruto's Chakra is full the gauge over the top of his life bar at the top of the screen will read "Max."
Release either Rasengan, or use your Chakra and press down on the analog stick of the Wii Nuncuk while activating the jutsu to initiate Naruto's Nine-Tailed Berserker form. Use the Nine-Tailed Berserker form to finish off Gaara with the a series of attacks; any attacks from the Nine-Tailed Berserker will work.