Suggested by superduperawesomeguy Dr Manhattan is a being that we can barely even comprehend from Watchmen. His power are nigh unlimited but with the Infinity Gauntlet so is Thanos. Thanos also obtained the Cosmic Cube at one point so mixing both abilities in would increase his abilities even further and in base mode he is already about as strong as the Hulk if not stronger. I don’t think Manhattan would be able to last against such a fighter as Thanos will overwhelm him with an all out offensive. It’s just nearly impossible to stop all of his attacks and eventually some will land. Thanos wins.