This episode is awesome.
SM manage to turn what should have been a stomp into a development episode, and showed remarkable fidelity to the characters they've built up so far.
I'm not happy about the outcome (for tangential reasons) but I really appreciate how this unfolded.
...
Here's a write-up. Spoilers, obviously.
-Ash beats Faba
-Guzma beats Ilima
-Hau beats Oak
-Lana beats Mallow
Guzma defeated Ilima by sandwiching the baby Mega Kangaskhan between the mum and Scizor, then quickly flanking the mum with X-Scizors and returning to place. The adult Kangaskhan wouldn't attack over the baby, and Scizor didn't have trouble dodging the baby's attacks.
Hau beats Alolan Exeggutor with Focus Blast after Thunderbolt did nothing. He used Quick Attack to dodge Dragon Hammer, exposing the neck and leaving a big target for Focus Blast.
Lana's Primarina learned Icy Wind. Seeing this, Mallow lost her nerve and tried to recall Tsareena, but Tsareena refused to give up the fight. Lana and Tsareena convinced Mallow to find her courage and continue to battle. Bloom Doom was successful but was negated by Oceanic Operetta. Primarina then finished off Tsareena with Aqua Jet.
Tsareena didn't do any damage to Primarina, I think. Even with the type-advantage the power/experience difference was far too great.