In episode 733 ” Attack on Celestial, Luffy’s King Kong Gun of Anger ” Luffy comes face to face with Heavenly Demon Doflamingo. Gatz announces Luffy’s Comeback in the fight and the fight between the two emperor’s resumes reaching towards its climax. After consecutive attacks by Doflamingo Luffy is sent flying and crashes into the One of them is the series’ protagonist, Monkey D. Luffy, and the other is Donquixote Doflamingo a Celestial Dragon, and one of Luffy’s greatest opponents. You’re going to find out who the stronger character is! As was evidenced by their fight in both the manga and the anime, Monkey D. Luffy is the stronger of the two characters. Out of story reason: Luffy is usually going to beat the main bad guy of the arc. There were people other than Luffy on the island who could have successfully challenged Doflamingo other than Luffy and Law(Fujitora, Sabo arguably Zoro) but they would be given their own reasons for not fighting Doflamingo sanji would have more stamina than luffy would in gear 4, Stop this headcanon sanji is faster or on par wit luffy right, Stop the headcanon. No way he will ever be on par with Luffy Without RS he couldn't even beat gifter. There's no way rs is on par with gear fourth. I like sanji too but put him where belong. Don't push your headcanon here .

in which episode luffy beat doflamingo