Originally Posted by Evil Vegeta

I know you were joking.

Everything I quoted from was in the manga. Cell was laughing and talkin about finishing it, and that's when Goku told Gohan to let his power explode. Cell was prepared to finish it, but Vegeta intervened, and Goku yelled "now", since there was an opening. Gohan clearly won because of Vegeta weakening Cell's defenses. Cell had no remote chance to defend himself at that point, so that doesn't make Gohan stronger.

Besides, Cell was holding back. He didn't release all of his power as well.