Pokémon is one of the most iconic anime of all time, and much of that is thanks to its original hero, Ash Ketchum. For 25 years, Ash traveled across the world and went through countless Pokémon battles in his pursuit of becoming a Pokémon Master, and when he finally retired as the protagonist, it was hard to deny that he had at least reached a semblance of that goal.

Few anime characters are as iconic as Ash Ketchum, but that doesn’t mean everything in his story was smooth sailing. For every incredible high in Ash’s career, there were just as many terrible lows, and by the end of his story, Ash’s journey in Pokémon was filled with numerous battles that were either major highlights of his career or the biggest stains and humiliations he’s ever had to endure. A few of those battles are especially worth highlighting, as each one highlights just how much growth Ash went through and how great it was to watch.

10 Ash Vs. Ritchie At The Indigo League Conference

Pokémon Episode 79

In the fifth round of the Indigo League, Ash was pitted against his new friend and rival Ritchie, although he almost missed the battle due to an impromptu scheme from Team Rocket. Most of Ash’s team was left exhausted from the experience, forcing Ash to eventually bet it all on Charizard, but due to Charizard’s refusal to fight, Ash was disqualified and only got as far as the Top 16.

It’s one thing for Ash to lose a major battle, but between how exhausted his team was and how Ritchie only beat Charizard by a technicality, Ash’s loss to Ritchie in the Indigo League Conference is frustrating because it was due to factors completely out of his control as opposed to his lack of ability. The loss can be excused by being so early into Ash’s career, but that doesn’t change it being as bad a loss as it was.

9 Ash Vs. Alain At The Lumiose Conference

Pokémon The Series: XY Episodes 130-131

In one of the biggest highlights of his career, Ash fought his way to the finals of the Lumiose Conference against his new rival, Alain. Ash boasted one of his strongest teams to date, most notably Greninja with its powerful Battle Bond ability, but after a long battle, Greninja eventually fell to Alain’s Mega Charizard X, leaving Ash as the runner-up of the Lumiose Conference.

As frustrating as it was to see Ash lose again when he had a genuine chance of becoming a champion, he still put up an incredible fight against Alain, and it was so close that it easily could have gone either way. Ash’s loss to Alain is one of his most infamous, but at the end of the day, Ash’s battle with Alain is one of his best for showing just how much Ash had grown as a trainer, even if he still lost.

8 Ash Vs. Wulfric At The Snowbelle City Gym (First Battle)

Pokémon The Series: XY Episode 120

As Ash made his journey through the Kalos region, he eventually made his way to Snowbelle City to battle Wulfric, the eighth and final Gym Leader. Wulfric’s strategy had him use hail to make his Avalugg invulnerable with its Ice Body ability while constantly chipping away at the health of Ash’s team, and that, combined with Ash’s lack of control of Greninja’s Battle Bond, led to a devastating loss.

Ash has lost to plenty of Gym Leaders in the past, but his loss to Wulfric was the most one-sided loss he had in ages, a perfect reminder that he was nowhere close to mastering Ash-Greninja, and he was so distraught that he even fought with Serena when she tried to cheer him up. Few fights have affected Ash emotionally as his first loss to Wulfric, and while he picked himself up for their rematch, it was nonetheless a big loss for him.

7 Ash Vs. Brandon At The Battle Pyramid (Third Battle)

Pokémon: Ruby & Sapphire Episodes 189-190

After two losses to Brandon, the head of the Battle Pyramid, Ash was putting out all the stops for their third battle by bringing back Charizard, Bulbasaur, and Squirtle, three of his oldest and strongest companions. The trio’s power helped pave the way for a climactic battle between Pikachu and Brandon’s Regice, and eventually, Pikachu won, and Ash finally succeeded in conquering the Battle Frontier.

It’s one thing for Ash to bring back some of his most iconic Pokémon, but after losing to Brandon twice in a row, seeing Ash finally come out on top was incredibly cathartic and a perfect showing of how strong Ash had become. The fact that Brandon made Paul’s brother retire from being a trainer and was someone Paul couldn’t even touch made Ash beating him even better, and it’s still one of the biggest victories of his career, by far.

6 Ash Vs. Cameron At The Vertress Conference

Pokémon: Black & White Episodes 106-108

For the quarterfinal round of the Vertress Conference, Ash was pitted against his new friend and rival Cameron, and Ash was having a surprisingly easy time, eventually ending up with a 3-1 advantage. All of that changed when Cameron was down to his Riolu, however, as a sudden evolution to Lucario gave Cameron the power to defeat Ash’s remaining team and knock Ash out in the quarterfinals.

It’s one thing for Ash to lose a tournament, but his loss to Cameron was especially bad because of Cameron's utter incompetence with things like not understanding type matchups and somehow only bringing five Pokémon to a six-on-six battle. Ash would have easily won were it not for the blatant plot armor of Cameron’s Lucario, and because of that, Ash’s loss to Cameron is a bad one purely because his opponent wasn’t someone who had the skill to justify his win.

5 Ash Vs. Professor Kukui At The Manalo Conference

Pokémon: Sun & Moon Episodes 141-144

Following his victory against Gladion at the Manalo Conference, Ash was crowned the first champion of the Alola League, but he still had one last challenge to overcome: an exhibition match with Professor Kukui. Kukui gave Ash one of his toughest battles in ages, even recruiting Tapu Koko as his final Pokémon, but after a hard fight, Ash defeated Kukui and solidified his status as Alola’s champion.

When Ash won the Orange League and conquered the Battle Frontier, his victories were quickly undermined by Gary beating him in battle and reminding him that he had more work to do, and Professor Kukui could have easily fallen into that role. Fortunately, Ash’s victory over Kukui showed that he was finally at a level where he could be seen as a true champion, and it was an incredible moment that highlighted why Pokémon: Sun & Moon was so great.

4 Ash Vs. Elesa At The Nimbasa City Gym

Pokémon: Black & White Episode 50

Ash’s journey through Unova eventually pitted him against Elesa, the Gym Leader of Nimbasa City. With Elesa being an Electric-type Gym Leader, Ash was confident he only needed Palpitoad to win to the point that it was the only Pokémon he brought with him, forcing him to run to the Pokémon Center to get more Pokémon, but despite all that, Ash would eventually come out victorious.

It’s one thing for Ash to be overconfident, but he took that to another level against Elesa by only bringing a single Pokémon with him and forgetting that Elesa’s Emolga was a Flying-type, even though Iris also had one. Ash might have won the battle, but Ash’s battle with Elesa is embarrassing because of the incredible level of incompetence Ash displays from start to finish, and it’s easily one of the worst moments in the Pokémon: Black & White anime, by far.

3 Ash Vs. Paul At The Lily Of The Valley Conference

Pokémon Diamond & Pearl Episodes 186-188

In the quarterfinals of the Lily of the Valley Conference, Ash was once again pitted against Paul, marking the final chance he would have to prove that his way of handling Pokémon wasn’t wrong. Unlike in their previous battles, Ash held his ground until they were both left with one Pokémon, Ash with Infernape and Paul with Electivire, and after a hard-fought battle, Infernape finally won Ash the battle.

Diamond & Pearl was the first time a rivalry was at the center of the anime’s plot, and sure enough, Ash finally defeating Paul perfectly showed off how much their rivalry had made Ash grow as a trainer and was nothing but cathartic to watch play out. No rival character before or after Paul has ever challenged Ash on such a physical and ideological level, and Ash finally overcoming him is still one of his biggest victories, to date.

2 Ash Vs. Paul At Lake Acuity

Pokémon Diamond & Pearl Episodes 131-132

Following Paul’s devastating loss to Brandon, Paul’s brother, Reggie, suggested that he and Ash have a battle so they could test each other’s abilities. That battle eventually took place at Lake Acuity, and despite Ash’s best efforts and Chimchar even evolving into Monferno, Ash suffered a devastating loss with his team being easily defeated while he, in turn, could barely touch Paul.

It was one thing for Ash to lose to Paul again, but his loss at Lake Acuity was thanks in large part to him letting personal feelings dictate the battle, something Paul always argued against, so Ash’s loss to Paul at Lake Acuity was bad not just because it was so one-sided, but because it essentially validated everything he disagreed with about Paul’s ideology. Ash would grow tremendously from the battle, but that doesn’t change how it was easily the most devastating loss of Ash's entire career.

1 Ash Vs. Leon At The Masters Eight Tournament

Pokémon Journeys Episodes 129-132

After making it to the Masters Eight Tournament, Ash fought his way into the final match against Leon, the strongest trainer in the world. Even with permission to use Mega Evolution, Z-Moves, and Dynamax, Leon still gave Ash his toughest battle yet, but against all odds, Ash and Pikachu emerged victorious and Ash was crowned the new Monarch of the World Coronation Series.

After watching Ash try and fail to come out on top more often than not for over 20 years, Ash defeating Leon and becoming the world’s greatest Pokémon trainer was the ultimate cathartic moment for any fan of the anime, especially with the gorgeous animation and the montage of all of Ash’s Pokémon cheering him and Pikachu on. The battle with Leon is undeniably one of Ash’s greatest battles in Pokémon, and there was no better way to retire Ash from the Pokémon anime.