Yeah San reminds him of Sanji
Technically 3rd commanders are #4 in their crew though lol.
Like it's actually an interesting dynamic:
- Luffy took out Mr. 3, who is technically the #4 member of Boroque Works
- Hatori was defeated by Luffy, Sanji and Usopp, and was the #4 member of Enel's group (Ohm and Shura had lower trial success rates). Funny thing though is that Shura wasn't beaten by Sanji, but by Wyper.
- Blueno had the 4th highest Doriki, defeated by Luffy
- Thriller Bark is weird, but I guess if you consider Ryuma and Absalom to be the #2 and 3 fighters, then Usopp and Chopper technically fighting Perona/Hogback as the #4/5 sort of fits this point. But there's argument that Perona is just broken and thus the strongest member of crew rofl.
- Dressrosa is an odd one. Diamante, Pica and Trebol don't actually have a ranking. And if we are being frank, Diamante goes down 4th to last and Pica goes down 3rd to last, which doesn't even fit Zoro's general placement of fights (but more on that in a minute). Kyros did technically fight the 4th to last villain. Law technically defeated the 2nd to last villain (Trebol) instead of Zoro, but it makes sense because of Laws relevance/involvement in the plot.
- Luffy took out Cracker, 4th in his crew. Snack, alleged 5th in his crew, wasn't even important to the arc lol
So it's interesting here because even with that jumbled mess above (which doesn't necessarily fit any rules about the 4th strongest), Jack and Pero's being the #4/5 threats this arc and them being handled by secondary characters makes, oddly enough, a lot of sense lol. It kept the realism in a way of allowing other allies to win fights, and not just Luffy'a crew, which has been a thing since Skypiea.
BUT, we have to technically shift down the rankings here due to Big Mom. Zoro may be fighting the #2 Beast Pirate, but he's fighting the #3 strongest villain this arc. Same with Queen from 3 to 4. Now you can see the irrelevance start to dwindle more, with Jack/Peros being 5/6 in the rankings there (not counting Apoo/Hawkins atm, but they certainly are more important).
And in this case, as with Law finishing off Trebol 2nd to last, it almost makes sense once again if he and Kid (or just Kid, not sure) take put Big Mom 2nd to last, after Zoro finishes off King. But these 4 remaining fights are technically the most relevant in the arc and they haven't been tackled yet.