And why are you belittling Vista!? WB commanders are not ranked by strength
+ he's the most experienced between Marco/Jozu and others
+
He was probably clashing with Rayleigh or Scopper Gabban during the flashback
So.... it really means nothing!
And the fight was not serious by either side!
+
Mihawk clearly stated before "I'm not like other brutes who go all out on mere rabbits"
He said that to Zoro, and he loves to test his opponent before he finishes... and the proof of that Mihawk vs Zoro which should have lasted for 1 second, but Mihawk loved to toy with him and test all his techniques first!
He basically was just standing telling Vista " won't you show me the flower blade style"
And Vista clearly didn't finish from demonstrating his highest techniques yet!
So naturally since he's interested... he delayed the duel for another time...
Mihawk character has always been about holding back, until you see everything from what the opponent can do! since his introduction!
Such characters I daresay are the most scary! Cause it feels like they have SEEN IT ALL! And they are at a time, so bored, wish to experience a new power from opponent!
Not belittling.
Shanks clashes equally with Vista's captain; Whitebeard. He splits the heavens, it was a greater clash than Whitebeard's other clashes with Admirals. Shanks's clash with Whitebeard > Admirals clash with wounded and weakened Whitebeard.
Clash of the Admirals vs. Whitebeard was like Big mom's clash vs. Marco, it creates huge shockwaves but nothing like splitting heavens, which happened between Shanks vs. Whitebeard, and Kaido vs. Big Mom.
Vista clashes equally with mihawk, mihawk asks permission to postpone the duel.
It's obvious that Yonko (Shanks) > Yonko commander (Vista).
If mihawk clashes equally with Vista, what chance he has against someone who is superior to Vista? No chance.