Exodus 8:18, But they could not. The Egyptian magicians were able to replicate in some similitude the first two plagues, but not the third plague, or any more from this point on. This teaches us two things. Satan’s is able to imitate YHVH’s miracles only to a point. Beyond that, his powers are limited.
Moreover, the magicians were able to bring two plagues on, but they were not able to reverse the plagues. Only YHVH through Moses and Aaron were able to accomplish this feat.
There comes a point that even the enemies of Elohim have to admit that “this is the finger of Elohim” (v. 19). When YHVH involves himself in the affairs of men, there is no doubt about it. It becomes evident even to his enemies.