Ash Ketchum has been the victim of some bad shenanigans as far as his Pokémon League matches are concerned. Whether he's up against a Pokémon from a later region, a Mythical Pokémon, a newly-evolved Riolu or a Meowth of all things, it hardly ever seems like he loses for the reasons he should. It isn't until the Alola League, over 20 years after starting his journey, that he's able to break his unlucky streak and become a champion.
Some of his worst reasons for losing come from his first-ever Pokémon league, the Indigo Plateau Conference. In his Top 16 match, he is pitted against his new friend Ritchie but ends up losing for several reasons that seem unfair, especially by the video game's standards. The anime obviously had to take creative liberties due to the minimalist storytelling of Red and Blue, and it's fine if they wanted Ash to lose, but there should have been better reasons for it. Under the right circumstances, Ash might have beaten Ritchie and advanced to the next round.
The first way Ash is cheated out of his win is by Team Rocket. Before his match is scheduled to begin, they make an attempt to steal Ash's Pikachu, and Ash is forced to fight off Team Rocket on his way to the stadium. This makes Ash so late that he almost loses by forfeit. What really makes this unfair, however, is how it wears out his Pokémon. Pikachu almost seems too tired to fight, while Pidgeotto is completely spent from having to drag Ash, Pikachu and Team Rocket's hot air balloon to the stadium as fast as it can.
The League knows about Team Rocket, so even if they didn't take any safety precautions or preventative measures against them, they could have at least let Ash explain his situation; they should have been willing to postpone the match by a day so that Ash and his Pokémon could be fully rested and prepared.
Another debatable reason for Ash's loss comes when he fights Ritchie's Butterfree. During the fight, Butterfree sprays a Sleep Powder on Ash's Squirtle, putting it to sleep and rendering it "unable to battle." In the games, sleep is just a status condition, so a Pokémon would still be considered eligible for battle until they were knocked out. However, in the early days of the anime, a Pokémon falling asleep constituted a loss in battle. It's hard to say whether Squirtle would have been able to withstand Butterfree's attacks long enough to wake up and fight back, but it at least deserved the chance.
This also might have been a good place to use Pidgeotto. Flying-type Pokémon have an advantage against Bug-types like Butterfree, so Pidgeotto might have been a better option than Squirtle, a Water-type. Unfortunately, since Pidgeotto was worn out before the match even started, there's no way of knowing how that could have turned out. To be fair, Pidgeotto has one of the worst losing streaks of all of Ash's Pokémon, so it might not have mattered.
From here, the battle goes pretty smoothly. Pikachu is even able to overcome its presumable exhaustion to defeat Butterfree and last against Charmander before being taken out. This is about what one would expect even if things weren't screwed up by Team Rocket.
The final nail in the coffin is Ash's Charizard. Despite forcing Ritchie to use his last Pokémon -- a Pikachu he could have easily beaten -- Charizard "refuses to battle" and takes a nap. Normally, a trainer with all eight badges can get any Pokémon to obey them, but Ash doesn't earn Charizard's respect until next season. With this, Ash is forced to forfeit the match for real.
So many things had to go wrong for Ash to lose against Ritchie. Thank goodness Team Rocket focuses on concessions during later Pokémon Leagues. It's also good that sleep is no longer a loss condition so that moves like Rest and Sleep Talk (which Ash's Heracross learns) can be used. Ash still has problems getting Pokémon to listen to him, but they manage to work most things out before important matches. If Ash were to rematch Ritchie, he would probably win.
