How the hell do you beat Doflamingo with Ivankov?

[UPRC]

Everything I've attempted so far has been easy as heck, but then there is THIS optional (?) fight right at the start, and it almost feels downright impossible. Even Kuma goes down without much of a fight, but Doflamingo feels impossible to lay a finger on. Anyone else having this issue? I've aced everything else so far, but I've lost this fight about five times now.

[Gube]

I defeated him by spamming the heavy sheild breaker

[TheSorrow55]

i skip this mission

[ESE]

I used the heavy guard break a lot and used a 4 hit Combo into tension hormones and death wink.

[barakah]

I swear to god I want to hang myself cuz of Kizaru

[Imaginationislife]

You need skill