WARNING: The following contains spoilers for Season 1, Part 3 Episode 1 of Pokémon Journeys: The Series "A Festival Reunion!" now streaming on Netflix.
In the premiere episode of Part 3 of Pokémon Journeys, Korrina returns stronger than ever to face-off against Ash in the World Coronation Tournament. The last time Korrina encountered Ash was during the XY series where she eventually had a Gym battle with him at Shalour City. It was a close and intense match, but Ash managed to scrape by, taking Serena's advice to use his own style during battle.
This is the first battle against a Gym Leader Ash has had during Journeys and also the first time Journeys reveals Mega-evolutions as well. Though Ash doesn't face his Riolu off against Korrina's Lucario, he does have the Pokémon spectate the match while his Gengar and Dragonite take to the stage.
Goh and Ash fly over to Kalos for the Battle Festival Challenge, a quick and easy way to rack up wins for the World Coronation Series in one swoop. As Goh is distracted catching Kalos Pokémon, Ash fights against nearby trainers so he can raise his ranking. Off in the distance, a certain Pokémon's aura is sensed by Riolu, that Pokémon being none other than Lucario. Not just any Lucario, it's indeed the Lucario owned by Shalour City Gym leader Korrina.
Like Ash, Korrina is also here to join the Battle Festival Challenge. The two reminisce over their Gym Battle, as Ash gloats about his victory against Korrina. Meanwhile, Riolu is looking up to Lucario like some sort of idol. Ash trains Riolu a lot, enough to make Pikachu jealous in a later episode. Perhaps his ulterior motive is to earn a Lucario though by gaining the max friendship level with his Riolu. Luckily, it seems Riolu is enamored by Lucario and would someday want to evolve into one too.
Unfortunately, Ash does not send Riolu nor Pikachu out for this battle against Korrina. Instead opting to throw in some of his newly caught Pokémon. A Riolu vs. Lucario match-up would have been entertaining, but likely result in a loss for Ash. Maybe he can have another rematch with Korrina, next time sending out a Lucario instead.
Korrina's Mienfoo, which fought against Ash in XY, has evolved into a Mienshao. Ash throws in Gengar for a match-up, and right off the bat tries using the rocky terrain field to his advantage. After smacking Gengar with an Acrobatics, Korrina uses U-turn to automatically swap Mienshao out with Lucario. She does this after Gengar uses Psychic on the rocks, realizing then that Ash had a super-effective move on his Pokémon. Lucario's Bone Rush easily knocks out Gengar, causing Ash to send Dragonite out despite not taking down any of Korrina's Pokémon.
Dragonite, however, might be Ash's strongest Pokémon currently. Ash uses Dragon Dance on Dragonite to boost its Attack and Speed. As the Pokémon is spinning, Mienshao's attacks end up increasing the speed of Dragonite's spin, possibly increasing its boost in the process. With this boost, Dragonite was able to smack Mienshao down with a Dragon Claw, knocking it out. Mienshao managed to land a couple of hits with High Jump Kick, but Dragonite's HP is so massive it's able to eat those kicks.
With Lucario back in the ring, Korrina pulls out her secret weapon: Mega-evolution. Playing it cautiously, Ash goes back to Dragon Dancing to boost Dragonite's stats. With Lucario's stats also boosted, Ash knows he has to hit hard and fast to take the Pokémon out.
The amount of time it takes to use Hyper Beam is too long though, and Korrina sees an opening to hit with Aura Sphere and Power-up Punch. Somehow, Dragonite still stands after that flurry of hits. Pushed into a corner, Ash comes up with another creative strategy using the battlefield to his advantage. He makes Dragonite flap its wings with Hurrican so hard that rocks fly in every which way, and audience members fly from their seats. These rocks serve as a way to distract Lucario, but it manages to escape the winds and use Power-up Punch. Dragonite also jumps forward with Dragon Claw though. Both Pokémon are seriously damaged, but in the end, Lucario goes down.
It's a little disappointing Korrina lost yet again, but there is still time for her to raise her ranking and rematch Ash later down the line. Despite losing, Riolu was genuinely impressed by their match, and likely further inspired to evolve into a Lucario someday.