Okay, so while waiting for the next chapter I had time to overthink things.
Rereading the fight, unless I missed something El Cucaracho hasn't made a serious attempt to dodge Pete's attacks, meaning he's still isn't being serious. So in his previous fights, when did he start dodging? Against Beatdown, it was after he got that surprise elbow to the jaw, and against Violence Incarnate it was after that weird "hit the ground and channel the force through my own body" attack he did.
Since that attack from VI is the last kind of thing you'd expect, I think it was like Beatdown's elbow in that it was a sneak attack that went past Cucaracho's awareness. I think hitting him with one of those attacks is what triggers him to start dodging blows. And in the ending of this chapter, Pete just kicked Cucaracho in the back of the head while going so fast even Monkey couldn't see it. The fighters in the stands speculated that Pete couldn't take Cucaracho by surprise due to how predictable his style is, but I suspect that in that moment he was so fast that wasn't an issue anymore.
So if my prediction is right, next chapter is when Cucaracho gets serious.