I recall seeing an episode of one of the various Power Rangers shows. I couldn't tell you which specific series the episode was from, except that I'm pretty sure it wasn't from the original series, as I remember the original Rangers team pretty well, and I have a strong sense that this was a later show with a new team that I wasn't familiar with. I'd guess that I saw this episode in the late '90s or early 2000s. It could possibly have been the mid-to-late 2000s. Definitely wasn't any time in the past decade.
The plot of the episode mostly focused on a young, male Ranger of Asian descent, with short black hair which was somewhat spiky, I think. I have a vague sense that he was the Blue Ranger of that team, but I'm not certain. I believe the character was going through some sort of crisis of confidence in the episode, possibly involving him struggling to make progress in his martial arts training. I recall there being a much older Asian man, possibly a relative (grandfather?) of his, who offered him guidance during the episode.
I believe the Ranger also fought the same monster one-on-one at least twice in the episode, possibly three times, and lost all but the last fight. Immediately after winning that last fight, he then adopted a flashy-looking kung fu stance, which stood out to me, because although Power Rangers pose a lot, I'd never seen one adopt such an overtly kung fu style stance in any other episode. Can't recall the shape of the stance exactly, but I think it was a low stance with both arms outstretched, something like the one in the image below.
Can't remember what the monster looked like, except that I'm pretty sure it was just a stuntman in a costume, who was therefore able to perform in martial arts fight scenes, similar to the Zoanoids in the live-action Guyver movies.
I also have the sense that the Ranger's face was visible in the final fight, so he may have fought in his street clothes, or in costume but unmasked. I don't recall any of those giant robot/Megazord fights in this episode, but I can't say with certainty that there weren't any. I don't recall any other Rangers being present in the fight scenes I've mentioned.