@etheral_dreams: Azula was on the ropes all right,a weird low showing on her part, but once Zuko joined the fight Katara was utterly overwhelmed
Azula is ridiculously agile, Aang couldn't even pin her down( granted the Dai Lee helped, but it's still pretty impressive she outperformed an airbender in that regard)
She also was casually dancing around Zuko when they first fought,and also disarmed Suki without using bending, I don't think Korra has much of an advantage h2h tbh, especially since she has Zuko to worry about also.
I think if Korra wins this she needs to be aggressive with airbending. Aang's problem was that he was too passive in nature, and was mostly on the defense in fights. Zaheer, and Korra herself at times showed how powerful it can be if used more offensively. Both siblings would not be as good against an aggressive airbender, I feel.