Yes. Simon can undoubtedly beat Goku without even expending his absolute power. As Goku powers up or transforms, Simon will probably just create a universe-sized mecha to utterly annihilate the Saiyan.

Why is Simon so powerful?

Simon has the ability to use Spiral Power because the humans of his universe are Spiral Lifeforms. This is because humans have helix-shaped DNA. By the end of the series, Simon is the most powerful spiral being who possesses limitless Spiral Power.

Is Gurren stronger than Goku?

K.O. Wiz: Goku may be strong and fast, but Tengen Toppa Gurren Lagann is just better in every way. Boomstick: Goku had a good plan to kill the pilots but the Reality warp abilities are just to much for him to handle.