Perhaps it's because he is so strong with the combustion ability. All power must come at a price, and mabye Combustion Man's was concentrating on his combustion to the exclusion of all else.

Well, I'm 100% sure Jeong Jeong is better than the insane Azula. Zuko managed to block her attacks and fire some good attacks at het. Since we all agree Jeong Jeong is more powerfull than Zuko, I think we can assume he can do that to. Maybe even a little better. But the big difference it that Jeong Jeong would never have made the mistake Zuko did, so Jeong Jeong would have pwnd her at that moment. It took insane Azula about 10 seconds to generate lightning, measured from the first spark to the moment she released it. That is certainly enough for a good bender to take her out. And it took Jeong Jeong 3 seconds to put up his massive wall of fire to stop Zhao's fleet. And then he wasn't boosted by the comet! So Jeong Jeong pwns insane Azula!

In book 2 chapter 1 it took Azula a little 3 seconds, also measured from the first spark to the moment of release. In "the chase" it took her a little less time. So in my opinion: Azula might tire Jeong Jeong by shooting blue flames at him for a long time, but we don't know exact how good Jeong Jeong's stamina is, but let's just assume Azula her's is better. When he get's tired she could deliver the finishing blow with lightning, but if he isn't tired enough, that 2 or 3 seconds may be enough to launch blast of fire at her. That blast could burn her and hurt her alot and knock her off balance. She then could electrocute herself or give Jeong Jeong more time to launch another blast and finish the fight. But seriously, 2 or 3 seconds in a fight is a DAMN lot. And experienced bender will never let that opportunity slip away. It could give Jeong Jeong enough time for the blast. The lightning may hit him first, but then she doesn't have time enough to avoid Jeong Jeong's attack and she get's hurt anyway. So in my opinion it's still a 50/50 situation between the 2 of them. If the 3 seconds are enough for him to launch a blast, he will win. If not, Azula will win. But we can't say that for sure, but I think 3 seconds are enough. And it may not be wise for Jeong Jeong to create another giant wall of fire if Azula is to close. But if she is still like 100 foot away, it might be. And at the moment she bends her way trough it he strikes. But if she is to close, she strike Jeong Jeong. So I realy think they are evenly matched, when both sane. It sure would be a nice fight. 50/50 in my opinion.

You're forgetting her other lightning strike in the finale, where it took her all of two seconds to spin around once, lie down in a comfortable position on a rooftop, and then launch her lightning bolt at Katara. So Azula is capable of summoning lightning at Ozai speed.

But why wouldn't Azula have tried her hardest. In "the avatar state" on the ship, she pushed herself to the limits! She was realy focusing, and trying as hard as she could. But you bring some good points. But I'm still 100% sure Jeong Jeong could kill the insane Azula. Zuko nearly did untill he god arrogant and stupid. A mistake Jeong Jeong would never make, because concentration and discipline is what he relies on during firebending. But the sane Azula could kick Jeong Jeong's ass. But it would be a difficult fight for her. VERY difficult. I give it now a 60/40 in favor of Azula. Jeong Jeong has a chance to win. But there is one thing I'd like to say. Jeong Jeongs all destoying walls of fire are created faster than lightning. And that walls can't be dodged. There where created under a second! And can destroy 20 tanks in one time. So if that wall hit's Azula is DEAD. But that was during the comet, but Azula's fastest lightning was during the comet to, and still the wall was faster. Faster than even Ozai's lightning.

Well, Azula couldn't jump out of the way, because the wall was as wide as the whole street. And she can't jump over and 30 meter high wall. And I'm sure he could have made them wider. And IF it hit's Azula, she's dead. No way she could survive somthing that can take out 20 tanks in one hit.

I'm not talking about that one. And we already had that discussed. That wall was just to force Zhao's ships to go on shore. And he didn't want to harm anyone! We agreed on that. I'm talking about the one during the comet. Yeah, I know their power was boosted by the combet, but so was Azula's 2 second lightning.