A very "eh" Fighting type pokemon.
The only great thing about Lucario in PvP is its ability to resist 9 damage types thanks to his Steel-type, but other than that, it's not entirely great because of his 1-bar STAB Close Combat & Flash Cannon, since it'll take too long to charge compared to other pokemons with 2 & 3-bar moves. His only reliable Charge move is his 2-bar Shadow Ball, but sadly, it has no STAB damage & Ghost isn't really meta in Great league if I'm not wrong.
However, investing 10k Stardust before evolving is still a wise choice anyway, so if you have to, I'd say pick Close Combat & Shadow Ball.