Sanji was the chef of the Straw Hat pirates and one of the crew's strongest heroes in One Piece. Alongside the intrepid Monkey D. Luffy and the standoffish Zoro, he diligently protected weaker allies from harm - especially Nico Robin and Nami for reasons extending beyond mere chivalry.
However, Sanji Vinsmoke is not invincible. He's met his match on several occasions, extending to his earliest days on the Baratie. By identifying the anime characters he could defeat and those beyond his ability, we can better appreciate how powerful the chef was even before training under Ivankov at Kamabakka Kingdom.
10 COULD BEAT: Iida Has Speed, But Low Striking Power & Durability (My Hero Academia)
Tenya Iida has a decisive speed advantage over Sanji, especially now that he can put his thrusters into overdrive for a prolonged period of time. However, he is exclusively a melee fighter with massive deficits in strength and durability compared to his culinary opponent.
Sanji was powerful enough to break Jabra's iron body and even crush several layers of stone in a single kick. If his foot connects with Tenya's in a close-range battle, he'd likely shatter whatever bones he hit.
9 WOULD LOSE TO: Rock Lee Is Virtually Imperceptible When Accessing His Gates (Naruto)
Rock Lee's fighting style mirrors Sanji's own -- both are melee intensive fighters who depend primarily on powerful kicks for success. However, the taijutsu expert was formidable enough to destroy giant meteors in a single blow, a feat that Sanji would struggle to match.
Even if he could, Lee was able to move faster than Gaara's automated sand or Sasuke's Sharingan could perceive him during his battles in the Chunin Exam. This affords him many opportunistic strikes against the chef, ones that would quickly overwhelm his comparatively lesser reflexes and agility. He would not have the advantage of a confined space as he did when fighting Ramen Kenpo, assuring his defeat.
8 COULD BEAT: Sanji Has Defeated Hired Guns Like Spike Before (Cowboy Bebop)
Spike's fighting style plays off his opponent's momentum and turns it against them. Like Sanji, he almost exclusively relies on kicks in close quarters but is also comfortable with medium-range gunfighting.
However, Sanji was powerful enough to send a sea king flying in a single hit and dodge the gunfire of multiple marines (as he did in Enies Lobby and more directly against Mont Blanc Cricket). Consequently, the bounty hunter would be overwhelmed in every aspect of the battle.
7 WOULD LOSE TO: Sanji Has No Means Of Harming Smoker (One Piece)
Smoker was one of the deadliest villains that Luffy faced in the original series. His Logia fruit was capable of suspending adversaries in air, suffocating them, and made him immune to all forms of conventional physical attack.
Without armament haki, Sanji has no tangible means of harming the marine and would be hopelessly unprepared for an engagement. His only reprieve would be to retreat, though with Smoker's extendable limbs and flight, even fleeing is unlikely.
6 COULD BEAT: Sanji Has Clashed With Swordsmen Superior To Levi (Attack On Titan)
Levi was fast enough to rip through the branches of sturdy trees undetected, strong enough to decimate the Beast Titan's hardened seventeen-meter body in seconds, and skilled enough nearly to avoid capture by Erwin Smith. However, Sanji has proven capable of defending against opponents above his skill through numerous clashes with Zoro, managing to deflect the man's swords using the flat end of his foot.
Considering that he also managed to keep up with and overcome Absalom (a man who could turn invisible), it follows that he'd be able to maintain Levi in his field of vision before parrying and defeating him.
5 WOULD LOSE TO: Sanji Would Fail To Dent Meruem's Carapace (Hunter X Hunter)
Meruem's base feats surpass Sanji's wildest dreams. The carapace surrounding his body was sturdy enough to withstand hundreds of hits from Isaac Netero, all powerful enough to obliterate stone columns and shake an entire crypt to its foundations.
Capable of obliterating multiple targets in the blink of an eye with his tail, the King could rip off Sanji's leg just as easily as he did the Hunter Association chairman's and thereby ruin his odds of success.
4 COULD BEAT: Sanji's Flaming Foot Is A Perfect Counter To Pride (Fullmetal Alchemist)
Pride was a particularly menacing homunculus since his shadows had range and durability. However, they had one specific weakness that Sanji could exploit -- a vulnerability to light.
By spinning rapidly and engulfing his heel in flames, the Straw Hat chef could simultaneously burst through the umbral shadows and strike down the villain commanding them. Considering his advantage in speed (especially in his final form), Selim wouldn't stand a chance.
3 WOULD LOSE TO: Sanji Wouldn't Recognize Haumea's Sinister Ignition Ability Until It Was Too Late (Fire Force)
Haumea was a skilled White-Clad cultist capable of rewriting the minds of her victims. She needed relatively close proximity for her attacks to connect but could bend subjects to her whim once her ignition ability was used successfully.
While Sanji outclasses her in virtually every aspect (strength, speed, and durability), his refusal to hit women would allow the villain the opportunity she needs for her mind-altering attacks to take effect.
2 COULD BEAT: Omaeda Is Comparatively Clumsy & Wields An Insufficient Weapon (Bleach)
Omaeda's ability to fly may allow him to define the pace of the fight against Sanji, though it wouldn't be a significant advantage given his limited weaponry. He is equipped with a single ball and chain that he is capable of throwing at the chef in hopes of crushing him.
However, Sanji was strong and skilled enough to deflect cannonballs thrown by Garp back onto the marines' battleship. It follows that he'd be able to turn the shinigami's weapon against him in a similar way, sealing his hilarious demise.
1 WOULD LOSE TO: Ludociel Is Faster & Too Well Armed For Sanji To Contend With, Especially In Margaret's Body (Seven Deadly Sins)
As the leader of the Four Archangels, Ludociel was already enormously powerful. He was stronger than Sariel and Tarmiel (two angels powerful enough to overwhelm Estarossa, who in turn could destroy castles with ease) and fast enough to force Escanor on the retreat.
Therefore, it follows that he'd have little difficulty overwhelming Sanji. Although being placed in Margaret's body limits the strength the zealot may wield, it also prevents Sanji from fighting back on account of his chivalry.