Actualy an essay time:
First of all, congrats to Misty for ending Ash's long unbeaten run that spanned TWO YEARS (and five days), which leads me to the below image.
Didn't think I'd bring this image up again after the Ash vs Leon battle, but it somehow became relevant again in this episode. Context, when the above interview happened in Robot Wars, it was after Razer's victory that advanced them to the grand final of series 6 against a Shiny Charjabug, I mean Tornado... which they lost. This is relevant as Ash's last on-screen battle against a trainer was when he beat Leon and then he goes and loses against Misty in this episode, it's almost as if I was a time-travelling infobroker when I made this image.
In all seriousness, I liked that they showed an Ash L here, and I know that saying that may make me sound like a d-bag following his ascension to world champ 2 months ago, but this episode shows that he isn't infallible, just like how Leon isn't infallible after losing to Ash. Having said that it was a close battle and I liked that Ash himself chose not to use Pikachu to battle Misty, where the opposite happened in EP007 where the latter decided he didn't want to battle her, something that even Daisy pointed out at the end of said episode.
Speaking of the Sensational Sisters, I hope they're doing a good job of looking after the Cerulean Gym, we don't want a repeat of what happened in AG134 where the gym had so many challengers, Daisy considered handing out Cascade badges in the meantime, then again the sisters were left in charge when Misty went to Alola in SM102 (where she mentioned the number of challengers) so I guess it'll be fine.
Dialing backwards into my episode review (which I'll rename "A Clauncher Duel"), this episode certainly felt like an OS episode, between music from said era being used and the many references, like Misty catching Ash with her rod (ala EP001) and her following Ash towards the end of the episode (ala EP003), and the premise of the episode being similar to "A Totodile Duel" (heck Totodile even appeared here too). Not to mention the bickering between Ash and Misty just like old times, it was amusing to see Ash sass Misty by saying Cilan's lure
actually catches fish, unlike the lure he got from Misty in AG187 and I initially forgot that when said lure was used in DP034, it didn't hook anything, a nice callback.
We knew from last episode that Ash is rotating his team in the miniseries and this episode further proves that Ash probs isn't going to be seen with a full roster and I suppose all of Ash's Alolan 'mons aren't in Alola no more given Rowlet was shown here, and whilst I'm on the subject of Ash's team this episode, I guess we can add Leavanny to the list of bug-types that don't freak Misty out, and it was sweet of him to comfort Psyduck when the latter thought Pikachu was coming its way instead of Misty.
One thing I do want to bring up regarding Ash's roster this episode is Corphish, and it was nice of him to get spotlight in this episode as with all his appearances post-Sinnoh, he wasn't really doing much, heck when he came back in Sinnoh, he wasn't even used in the Sinnoh League, but I did appreciate that he got a couple of new moves to make up for the lack of training in the last 10+ years, especially since he hadn't learned any new moves since AG. Same with Misty's Politoed, we haven't seen that since the 4Kids era (same with Azurill, this would be their first appearances in the TPCi era) and it has now become the Cerulean Gym's guardian deity, with an essentially enhanced paint job, moves-wise (other than Mega Punch, which carried over from OS).
I enjoyed the dynamic between Clauncher and Corphish, the two forming a bromance and when the former was caught by a very-hungry Team Rocket, who pointed out that Clauncher's claw is a delicacy (and Jessie being correct when she said "it's not like it's yours." when Misty told them to let go), Corphish rescued Clauncher and the pair sent Team Rocket packing... to then get ratio'd by Miraidon in the post credits scene.