Monkey D. Luffy is the main character of One Piece. He set out alone at a young age, and gradually he formed a crew, which came to be known as the Straw Hat Pirates. Luffy's journey has by no means been easy. He has fought some of the strongest pirates in the series.
The fights have been exciting, and they have kept the fans on the edge of their seats. The fights involving Luffy are always highly anticipated. In some of the fights, Luffy needed to work extra hard to beat his opponent. There's no doubt that Luffy will continue to fight characters who will give him a hard time in the future.
10 Charlotte Katakuri
Few characters had a better first appearance in the series than Katakuri. Katakuri is the strongest Sweet Commander of the Big Mom Pirates. Katakuri showed Luffy that he still had a lot to learn.
Katakuri used Advanced Armament and Observation Haki in their fight. Luffy was getting battered for most of the fight and only found his footing when he had the flashback about his training. Luffy had to use a new variant of Gear 4 and a future sight to beat Katakuri.
9 Rob Lucci
Rob Lucci is a member of CP-0. When he fought Luffy, he was still a part of CP-9. Lucci is ruthless, and he doesn't show mercy to his opponents. Luffy vs. Lucci is one of the best fights in One Piece. During their fight, Luffy was badly beaten up by Lucci.
Things weren't looking good for Luffy, and it seemed that he would collapse anytime. At this crucial moment, Usopp urged Luffy not to give up. Usopp's cries moved Luffy, and he made a final attempt to beat Lucci. The final push was successful, and the Straw Hats managed to save Robin and Franky.
8 Gecko Moria
Gecko Moria is the main antagonist of Thriller Bark. He is a former Shichibukai and the captain of the Thriller Bark Pirates. Moria possesses the Kage Kage no Mi, which allows him to steal the shadow of other people.
The former warlord also used to be a rival of Kaido, one of the Yonko, but clearly, age had taken its toll on Moria. Nonetheless, he made Luffy work really hard for his victory. After the fight, Luffy was completely drained, and he couldn't even move for quite some time.
7 Charlotte Cracker
Cracker is one of the three Sweet Commanders and the first to be introduced. He fought against Luffy in the Seducing Woods. Cracker's Bisu Bisu no Mi enabled him to create biscuit clones.
Luffy couldn't damage his biscuit clones even with Gear Fourth. Things were looking bleak for Luffy, and he had to rely on Nami's support to get a breakthrough. The fight was a clear indication that things would only get tougher from here on out.
6 Donquixote Doflamingo
Donquixote Doflamingo is the captain of the Donquixote Pirates and the main villain of the Dressrosa arc. He is a former Warlord and also the former ruler of Dressrosa. Doflamingo has the Ito Ito no Mi, which is a paramecia type devil fruit. The devil fruit allows him to create and manipulate string at will.
Doflamingo's control over his devil fruit is immaculate, and he has trained it to the point that he managed to awaken the devil fruit. Doflamingo easily defeated Law and even chopped off his arm, but the real challenge was fighting Luffy. Luffy was in dire straits when his Gear 4 ran out, and he was bailed out by other pirates, who managed to distract Doflamingo. After a difficult fight, Luffy finally managed to bring him down.
5 Enel
Enel ruled over Skypiea, where he was considered "God." He had easily toppled Gan Fall from his position. Enel combined Observation Haki and the power of Goro Goro no Mi together; this enabled him to keep track of everything that was going on in Skypiea.
Enel's reign as God came under serious peril when the Straw Hats made their way to Skypiea. Enel wiped out almost the entire crew with relative ease, and the only person who stood in his path was Luffy. Luffy's rubbery body made him Enel's natural enemy, but the latter had Observation Haki that enabled him to dodge attacks. In the end, Luffy's dogged determination paid off, as he managed to land a critical hit on Enel that sent him flying.
4 Arlong
Arlong used to be a member of Sun Pirates, who were led by Fisher Tiger. Like many fish-men, Arlong is a misanthrope. He went to East Blue after the death of Fisher Tiger and started his own crew— Arlong Pirates.
Being a fish-men made Arlong much stronger than any normal human. Luffy fought Arlong to free Nami from his tyranny. Along strength made it almost impossible for Luffy to gain the upper hand in the fight. Finally, Luffy used Gomu Gomu no Ono to finish Arlong once and for all.
3 Sir Crocodile
Crocodile is a former Warlord of the Sea. He is the only antagonist who has beaten Luffy more than once. Luffy's first two encounters with Crocodile ended rather badly; Luffy was left at death's door, and it was only due to Nico Robin that he survived to fight against Crocodile for the third time.
2 Hody Jones
Next up, we have Hody Jones. He has done a lot of bad things to spread hatred of humans on Fish-man Island. Luffy would have beaten him easily if Hody had stayed on land.
However, Hody was clever enough to take the fight into the water, where he had the advantage. Being a devil fruit user, Luffy had to go through a lot of trouble, but eventually, he defeated Hody Jones with Red Hawk.
1 Magellan
Magellan is the former chief-warden of Impel Down. His Doku Doku no Mi is a very lethal devil fruit as it allows him to create poison at will. He fought Luffy twice in the arc.
Luffy was at death's door after their first fight, and he had to seek Ivankov's help to survive. During their second meeting, Luffy used Mr. 3's candle armor to fight. The armor was a great help as it allowed Luffy to fend off Magellan.