In my knowledge, AI is software that is able to receive inputs and produce an output, with output changing based on its learning from provided by inputs.
As a result, is computer opponent in games such as FIFA, PES and more trivially, Ping Pong really AI algorithms?
Well, it indeed is. Maybe there is some kind of missconception about the concept of Artificial Intelligence.
As far as I know, close to graduating, I did an AI subject last year, and what we basically saw was path finding algorithms, among other things.
So imagine a map (not programatically speaking). Our character with AI (we will not move anything. Just execute) will search and reach all enemies before looking for the exit, or the goal, however you want to call it.
Enemies will keep moving, so the algorithm keeps searching them, even learning, if you program it to do so. That means it is not just a matter of "GO FROM A TO B".
That is possible thanks to some algorithms like A*, using Manhatan distance or however you want to implement those algorithms.
Imagine Fifa now, as your example. The computer, AI, has all the info at any time. Knows the position of every player. Divide the behaviour into 2 basics:
Same thing goes to League of Legends. If you can manage to make a "script", that would behave as an AI, as it can act without any supervision on its own, and probably do much better than most players. However you can configure it, you can know the position of all champions, know the Cooldown of all abilities, know from the position an ability is thrown and the first frame of direction, you can know the full path, so the AI will dodge at the minimum, etc.
As I mentioned, maybe there is a missconception of AI, like being a super extreme intelligent robot that can cook, clean, speak, and do Math homework, like a human would do. Maybe in the future.