I probably just got insanely lucky, but when I fought her, she used her invis and...hammer arm? I guess? her weak attack, basically, quite a bit. So what I did was punched her when I could, defended when she went invis, and used my own invis when she charged up her lazer (which she only did once). Then, once she was within range, I hit her with my 2 ghost rays. Reason I think it was complete luck: apparently the Tucker fight (presumably the third fight? when he's all beefed up?) is supposed to be hard, but he did nothing but go invis when I fought him.