Aqua Jet/Sucker Punch Glitch?

Question

In showdown, I was battling a Yveltal with a Feraligatr. I used Aqua Jet, which is priority, but when he used Sucker Punch, it failed. Can anyone tell me why?

Answer 1

If the target uses a non-damaging move or happens to act before the user, Sucker Punch will fail.
Source: Bulbapedia

If two Pokemon both use priority moves, then the faster one will go first. In this case, you were faster, so your Aqua Jet went first, causing Sucker Punch to fail.

Answer 2

Sucker punch has to hit first inorder to inflict damage if you hit before sucker punch sucker punch will fail