Plan A) Zoro jumps towards Pica, charging his Ashura or whatever. Donquixote fodders see him and say "Waaahh!! It's Pirate Hunter Zoro! We need to at least slow him down before Pica notices him! Let's do our best family!" And so they jump towards him, but Zoro footstools them using them as platforms to reach Pica in a very swift way. Pica will turn his back and punch Zoro's swords, but he will manage to hit him regardless in the face smashing him. Final panel will be showing Pica's back untouched and since he's made of stone he will die standing, with the bottom left corner that will say: "Never turning his back to the enemis, his back is unscathed! One Piece exists!"
Plan B) Pica summons another stone giant between him and Zoro, it will charge his stone punch with all his 4785832 megatons of brute force, but Zoro will take it, flying all over Dressrosa, but before hitting the Birdcage, the Kingu Panchu will hit him back making Zoro ping pong all over the island. But while he is flying, Hakuba will fly with him saying: "…" and then Cavendish will also appear saying: "I won't let you take all the glory Pirate Hunter Zoro! I will take down the stone monster and the glory will be all mine!!! I can already hear the ladies call my name "oooh Cavendish-sama, you were so brave when you defeated that other Supernova we totally don't care about, while you flew in the sky to save a country ruled by a Shichibukai!!! Kyaaaah Cavendish-sama, take me with you to- KAMABAKKA!!" - "YES MY FAME WILL SPREAD ACROSS EVEN THE OKAMAS!! Ah it's beautiful to be the star again~" And while Cavendish was dreaming all about it Zoro took down Pica sama, and Hakuba will stare in the readers face like he is in The Office.
Plan C) While Zoro flies towards Pica with all his might and intent to kill with a big stupid grin on his face thinking about Luffy and concentrating all his might to the slash, Pica does his ultimate move of just dodging the attack, and will hit Zoro and the others regardless.
Plan D) While Zoro is flying across the sky, Pica will do the same. Going out from the Stone statue, Pica will jump towards Zoro and the two of them will clash in mid air. Zoro will pierce him and drag him to the ground with him, while Pica will shout stuff like: "We will die together!!! Nonsense!!" But Zoro will reply with: "I won't die, I have friends that will help me!!!" And so Kanjuro and Kinemon will fly towards Zoro with a poor drawn Phoenix, while Kinemon will shout at him stuff like: "Zoro-dono, by rescuing you i require that you will hand over Shisui this instant!!" And Pica seeing that sword will think back of his adventures with the Family: "(If only i wasn't made of stone, then when we went to the ice continent where i fought that one eyed red giant i would have won and also took that Sword to improve my skills as swordsman!!"
Plan E): Pica realizes that he just needs to summon another stone giant in front of him, so that Zoro will have to cut the one in the back first leaving him time to punch everyone.