The Greatest

The Greatest is performed by Niki Watkins, who also sang The Joke is on You for the Season 4 episode, IGet Pranky. This song, The Greatest, is written by Michael Corcoran. He also wrote The Joke is on You, which is sang by the same person as this song. It is featured in the Season 4 episode IBalls during the Spencer/Marty montage.

Lyrics
You're the one, who changed the world for me

And you have never let me down if I fall

Now I know you're the greatest (one of all) (x4)

Now I know you're the greatest (one of all) Whoa, Oh!