Ash Ketchum is the perpetually 10 year old protagonist of the Pokemon anime series, which is now on its 19th season. Ash has traveled through seven different regions, picked up tons of gym badges, and caught tons of Pokemon during his many journeys, but he's perpetually come up short of winning an actual Pokemon League tournament. Sure, Ash won the Orange League way back in the second season of the show, but that "League" consisted of a single battle against a cocky dude named Drake who turned out to be way overrated. In "real" Pokemon League contests, the closest Ash has ever come to winning was in Sinnoh's Lily of the Valley Conference, where he lost in the semi-finals to guy who only used Legendary Pokemon.
However, that all could change next week. After being portrayed as a bit of an idiot in Pokemon: Best Wishes (the Pokemon series that took place in Unova), Ash returned to his veteran battling techniques in Pokemon XY: The Series and has gone up against some of the best Pokemon trainers the Kalos region has to offer. Ash is also fielding his strongest team of Pokemon yet, with the quasi-Legendary Goodra and a Greninja that can Mega Evolve (sort of) joining Pikachu, Hawlucha, Noivern, and Talonflame on his team. In the build up to competiting in Kalos's Luminose Conference, Ash has fought two Legendary Birds to a draw and was poised to beat the Kalos Champion Diantha before an interruption.
Over in Japan, Ash is currently in the finals of the Luminose Conference, the official tournament in Kalos. After beating his unofficial protoge Sawyer in the semi-finals, Ash is now going up against his other rival Alain in a full 6v6 Pokemon battle. Alain is the very definition of "OP", with a Mega Evolved Charizard that might be the strongest Pokemon to ever appear on the anime. Alain's Charizard has fought multiple Legendary Pokemon and won, and he's on his own quest to fight every type of Mega Evolved Pokemon in order to collect enough Mega Evolution energy to heal his friend's Chespin.
Going into next week's episode, Ash actually has a 3 to 2 advantage on Alain halfway through their battle. Two decades of training finally paid off for Pikachu, as the electric mouse wrecked Alain's Tyranitar and Metagross in convincing fashion. Ash also finished off Alain's Unfezant and Weavile, although at the cost of his Talonflame, Hawlucha, and Noivern. Alain still has a Bisharp on his bench as well as his Charizard, while Ash hasn't even used his Goodra or Greninja, arguably the two strongest Pokemon he's ever owned.
So why would the Pokemon anime finally pull the trigger and have Ash come up on top? If the rumors about Pokemon Sun and Moon are true, the Alola Region doesn't have a traditional gym and Pokemon League structure. We know the game uses "Island Trials" and "Trial Captains", which probably are a replacement for traveling to gyms and collecting badges. If there's no Pokemon League for Ash to conquer in Alola, why not have him finally win a real Pokemon league after 20 years of trying?
The Luminose Conference wraps up next week, so we'll see if Ash can finally pull off his long-awaited victory. However, there's a good chance there will be some sort of Team Flare shenanigans (Alain has ties to the shady organization and Team Flare has expressed interest in Ash's Greninja) but we could very well see a false finish of sorts. If you want to watch the dubbed English version of the episode, you might have to wait a few months. There's usually about a four month delay between the Japanese version and the English version that airs on Cartoon Network.