Simon and the most powerfull Gurenn Lagann. With everyone else combined spiral power vs The Living Tribunal.
Anyone doesn't know, Simon controls a Robot that use the "Spiral power" which is the power to constantly evolve and break the laws of physics. Its Strongest Incarnation fought an entity of the Universe itself. An entity that can make pocket multiverses and defy the laws of physics. And won by evolving to a level greater than that. Even surviveing an attack as strong as the Big Bang itself.