The last days I have been thinking in the match and how Raikou would react in such extreme situation, and then I finally remembered something important, her Lone Warrior Mode.
This state was introduced in her second interlude, and was trigered by she remembering her historical childs, and by doing so remembering her trauma that affect her motherly persona.
Lone Warrior Mode is a state in which Raikou enter when she is
under too much stress, a state in which she don't hold back with anything, just empty her mind from all troublesome problems and focus entirely in fighting and slaying her enemies (in the video she was even attacking seriously Kintoki who she see as her child and who she would never actually hurt). In exchange however of not holding anything back and crush things with an overwhelming power, her mental defences get incredible lower do to her unstable mental state, and such even mental spells from low level servants (Shikibu in the video is considered a low level servant) can affect her, so while in combat Raikou would be able to crush Dread if he end using a mental spell is likely that he would win.