A Kamui which failed to wrap Konan will apparently wrap a foe with better reflex than Konan...wow!
OT: Nagato wins. ST will make Kamui useless, because gravity affects space-time; Kamui would be nullified, either at process of wrap in close or long range. Nagato should be able to detect Kamui, due his sensory and further amplified shared of vision. He could kill him during the moment of wrap. He could also trick him into wrapping a clone, which, from the Kamui dimension, will attack Obito's transported portion of body. If none of the two strategies worked, he outlasts him.