@Jonkeon42 What? No, I don't. That's such a stupid accusation. I just know their abilities and am not a blind fanboy.
Zuko got rolled by Combustion Man (and that blast was no stronger than P'Li's) off a cliff.
Also, he doesn't have lightning, and given how we've seen how weakly fire holds up against explosions, fire is the worst type of bending to use against combustion benders.
Add in that P'Li especially (unlike Combustion Man) can bend nominal fire (you know, like Zuko does) and turn it into an explosion.
Zuko isn't Mako or kemurikage comic Azula (each of whom has the option to use lightning and instantly, at that).
His particular bending style is the worst to use against a combustion bender, and literal suicide against P'Li.
I actually love Zuko, but I'm not delusional like some of his stans are. I know that he can't beat P'Li because she can use his style against him and as fuel for her own.
And if we're using the old Zuko from "The Legend of Korra," then he's dead in ten seconds.
Seriously, do tell, what exactly is Zuko going to against P'Li, someone who can convert all his attacks into an explosion against which he has no defense?