The Warrior of Light and tournaments...

[Miyha]

I haven't played Stormblood yet, but in my experience they are either in the class quests, where you are still considered just a normal if talented person, or the MSQ where the tournament in question is between the various heroes of the realm in which case they are similarly strong.

^ This, from what I can remember. I don't really remember any specific "tournament-style" fight where you're obviously just going in to obliterate the little man; well, aside from the fact that you are the player character, have all the plot armor in the world, and are obviously going to fare better against the NPC. Usually. ._. In any sense, most of these "tournament-style" fights are also a bigger picture sort of thing. You may defeat the little man, but you're ultimately doing him and everyone else a service in doing so by using your victory to accomplish something bigger.

Since you mentioned spoilers, I'm going to guess the latest example of one such "tournament" you may be referring to is:

The Naadam. In which case you are a) a foreigner and no one has any idea who you are or what you have accomplished, and b) going up against multiple tribes of bloodthirsty/power-hungry Xaela and their quite powerful/scary leaders. Difficult and frightening for anyone, even the WoL. :P It was also with the purpose of winning the respect of said tribes (sort of) and (definitely) forcing them to fight with you in the liberation of Doma, so there's your "bigger picture/purpose" right there.