From what we saw, Turtonator was terribly outclassed. I'm judging from what we saw, and it was clear that Turtonator was no match whatsoever for Pikachu.
Again that was a training match. And plus we never saw the outcome of that battle. You can't say that oh well this pokemon has a weakness that can easily be exploited so that means that it must be weak, because having a weakness is not the same thing as being weak so it's not indicator of ones strength.