Pokémon: Twilight Wings

This callls it "Valerian Star Tournament", while the core anime refers to its own league by some other title, but who cares in the end, it's the same thing.

And without this miniseries we'd have again no connection to the weight of the championship, so it's canon is though a bit flimsy, it's perfectly acceptable, because it is needed to give the necessary weight to the core anime.

The first seven episode culminates in a certain poke-battle, nothing specific with its own value, but it still builds character for Leon adequately, so it's actualy good storytelling, even with some weaker/filler episodes, to give him - and the others - to create the World Cup League.

As usual, this spinoff/sideshow is better than the core, and rly not that long.