I'm not trying to be an ignorant fan and saying a character will beat another character far out of their league. It may just be I'm missing something entirely. But going based on the feats I know of Dark Schenider I think Sailor Moon would beat him using speed and hax. From what I know Dark Schendier is a Galactic Level Character (Destructive Capacity and Durability) with vague speed and several hax abilities (the three big ones being Eternal Atoms, meaning he can regenerate from Physical, Spiritual, and Abstract attacks on an atomic scale, Judas Priest which destroys things on a physical, spiritual, and abstract level, and Dispel Bound which cancles out spells). Well if that is the case then I don't see why if PIS/CIS is off that Sailor Moon wouldn't use Space/Time manipulation to win. Let me explain:
Speed Wise I am not aware of any feats that put Dark Schenider anywhere near Sailor Moon's range of speed. Sailor Moon is hundreds of billions of times the speed of light. This is the point I am the least sure of and if there is a speed feat that put him above that I apologize.
Assuming though that Sailor Moon is faster I don't see why she can't just freeze time. I checked through Dark Schenider's list of abilities. I have seen no resistance to Time Manipulation.Sailor Moon could also use her space/time manipulation to send Dark Schenider to the Big Bang (and she CAN do this without going there herself, she did it with the Sailor Crystals) or to the Big Crunch/Rip. If he only has galactic durability then he wouldn't survive that.
Still there is the matter of the Eternal Atoms right? The beginning/end of the universe probably don't destroy things on the spiritual and abstract level. Probably. Despite that she can send beings from other points in Space/Time to other points of Space/Time. In other words she could send Beginning of Series Dark Schenider to the Big Bang causing the one she is fighting to disappear from the timeline. However assuming that dosen't work on him due to it taking place in a neutral universe or some such Sailor Moon still might be able to destroy his atoms on all three planes of existence.
Sailor Moon has attacked people on all three levels before. Metallia was an entirely spiritual being and Princess Serenity defeated her with the Silver Crystal in the first arc. In the last arc Sailor Moon battles Chaos, an abstract entity (Chaos is the abstraction of the primordial non-existence before anything existed). In the future the strongest form of Sailor Moon, Sailor Cosmos fights Sailor Chaos (Chaos resurrected as a senshi) constantly.
But even if you say that wouldn't work it would at the very worst for Sailor Moon be a stalemate because while she can't destroy him he is frozen in time.
Am I just missing something?