The Semi-Final Frontier! (Pokémon the Series: Diamond and Pearl)

The Semi-Final Frontier! (Japanese title: シンオウリーグ準決勝！ダークライ登場！！ Sinnoh League Semi-Finals! Enter Darkrai!!) is the 189th episode of Pokémon the Series: Diamond and Pearl, and the 655th episode of the Pokémon anime. It first aired in Japan on August 26, 2010, and in the United States on January 22, 2011. It was heavily panned by audiences and fans alike, and is widely regarded as one of the worst episodes of the entire series.

Plot
After his shocking victory over Paul in the quarter-finals of the Sinnoh League, Ash discovers that his next match is against the strongest contender in the entire league: Tobias.

Why It Feels Like Cheating

 * 1) Just like Friend and Foe Alike, this is another infamous episode where Ash loses a Pokémon League match through contrived circumstances.
 * 2) This continues the horrible trend of Ash losing in the Pokémon Leagues.
 * 3) As usual with these types of episodes, it's a very unfair and mean-spirited episode to Ash.
 * 4) This episode seems to only exist so the creators could make jabs at the fans' criticism of Ash repeatedly losing in the Pokemon Leagues, which shows that they were incapable of taking criticism.
 * 5) False Advertising: This episode is part of the season known in the English dub as Sinnoh League Victors, but Ash gets knocked out of the Sinnoh League here and therefore does not claim victory.
 * 6) Except for Sceptile and Pikachu, this is also a mean-spirited and very unfair episode towards Ash's team, as, despite their best efforts, they get destroyed by Tobias' Darkrai (who takes out Heracross, Torkoal and Gible with minimal effort) and Latios (who defeats Sceptile (after defeating Darkrai) and Swellow very easily), and it's unfortunately a bad way to bring back Torkoal and Swellow, since we never saw them battle here until now, and they get quickly taken out (while Heracross and Gible had previously got wins before facing Tobias).
 * 7) Similar to Kanto, Ash loses in the most asinine way possible.
 * 8) * Tobias beats Ash with one Legendary Pokémon and one Mythical Pokémon, which are supposed to be illegal outside of the Elite Four and Championship rounds.
 * 9) * Latios' inclusion is kind of justifiable due to a rule change in the 2010 Pokémon World Championships, which allowed players to use one Legendary Pokémon on their team... but the same cannot be said for Darkrai, as Mythical Pokémon are still banned to this day.
 * 10) Tobias is one of the most unfairly overpowered characters in the series, as he easily beats Ash with minimal effort by using Pokémon that shouldn't even be allowed in the tournament.
 * 11) * What's even worse is that, unlike previous rivals that beat Ash, who both appear in the first part of the Pokémon League Championship or earlier, have memorable personalities and (in the case of Alain) understandable motives for wanting to win, Tobias is randomly shoe-horned in at the last minute and has no character other than the fact that he's a guy who has a Darkrai and Latios. Nothing else, nothing more. It feels like the writers just came up with him so Ash wouldn't win the Sinnoh League.
 * 12) * Unlike most, if not all of Ash's rivals, Tobias has extremely little buildup before his battle with Ash, only appearing in a few cameos. Some foreshadowing would have been helpful!
 * 13) Because of all the previous times that Ash lost, having him lose again here makes it seem like the writers treated this as a running gag - which is not true, as seeing Ash having his dream of becoming a Pokémon League winner get crushed through no fault of his own is both heart-breaking and downright infuriating.
 * 14) The Aesop of "You can't win at everything" had been completely driven to the ground after the Hoenn League arc in Advanced, and seeing Ash lose again only served to infuriate fans.
 * 15) Ash and Tobias' battle is a primary example of the "Diabolus ex Machina" trope. Given that Ash was storming through the Sinnoh League, even managing to defeat his rival Paul in the quarter-finals, it actually seemed possible that he would go on to win the whole thing. However, since he was never supposed to win an official league, Tobias was hastily written in just so that Ash wouldn't win and the anime could get to Black & White faster, which is really lazy writing.
 * 16) Tobias never gets called out for utterly overpowering poor Ash with both a Mythical and a Legendary Pokémon.
 * 17) Half-Bad Ending: Tobias ends up winning the Sinnoh League and gets away with his blatant cheating, which is incredibly unfair.
 * 18) This ended the Sinnoh League arc on a very sour note.
 * 19) Even though the match between Ash and Tobias has them using six Pokémon each, Tobias only needs Darkrai and Latios to sweep Ash's entire team. The episode never reveals who the other four of Tobias' Pokemon are.

Redeeming Qualities

 * 1) The animation and voice acting are still good as usual.
 * 2) Depending on your point of view, this battle was one of the most epic that Ash has ever participated in.
 * 3) Except for Tobias, every character is still likable. Heck, this is even where Team Rocket's Meowth is at his most tolerable!
 * 4) * It was nice to see Barry one last time before he departed from the group.
 * 5) * Despite being unlikable, Tobias commends Ash on defeating Darkrai and shows good sportsmanship throughout the battle, and his character design is passable.
 * 6) It was nice to see Paul (before he returned in Journeys), Cynthia (before she returned in Black & White) and Charles Goodshow one last time as cameos.
 * 7) Ash and Tobias' battle helped to show the true power and potential of Ash's Pokémon, especially Gible, Sceptile and Pikachu.
 * 8) The most epic and entertaining moments of the episode are when Ash flips his hat backwards (the only DP episode where he does this), Sceptile defeating Darkrai, and Pikachu's double knockout against Latios.
 * 9) Half-Decent Ending: Ash, Dawn and Brock say goodbye to Barry as he leaves, and the gang looks toward the future ahead of them.
 * 10) Tobias is only seen in this episode and is never seen or mentioned again.
 * 11) Given that Tobias won the Sinnoh League, this gave him the right to challenge the Elite Four and Cynthia. However, Cynthia is revealed to still be the Sinnoh champion in Black & White and Journeys, which heavily implies that either she or one of the Elite Four managed to defeat Tobias.

Reception
Despite having good ratings from critics, like a 7.4/10 on IMDb, this episode was heavily panned by audiences and fans of the show. It is often considered one of the worst episodes of the show.

Trivia

 * This is the only episode in Pokémon the Series: Diamond and Pearl to feature a Full Battle not involving Paul.