User blog comment:TerraBlader/King of them all?/@comment-24154900-20150617022933/@comment-3157150-20150617041821

I wouldn't so much call "OP" stupid as I would rather call it subjective. The exact same setup does not guarantee even similar results due to different levels of skill and different attack/defense styles.

Also, beating the DG while simultaneously beating Duke Fishron is not impossible, nor is it very difficult (assuming you know how to beat the DG easily enough). It just involves summoning Duke Fishron first (all you need is a Truffle Worm, no bosses need be defeated before you can summon him) and then dropping into an area where the DG can spawn, which can be set up in a pre-hardmode world quite easily with endgame equipment.