Proof is that Itachi said that even if they had support of other Akatsuki members that wouldnt change the outcome. Like I said, its rubbish, or do you really believe that Jiraiya would be able to take on two or more full Akatsuki squads? If you do, then you are just silly. Itachi alone is superior to him. And saying that Itachi was lying is not a way to avoid facts, its pure logic. Itachi was trully Konoha shinobi. And I remind you that Kisame was surprised when Itachi ordered him to retreat from hotel, he couldnt understand that decision. Why Amaterasu burned through frog belly intantly? Becuase Itachi was looking at it. Amaterasu burns relatively slowly only when its left by itself, but if Amaterasu user is focusing his eyesight on targed its engulfed in short seconds, like Madara, Hachibi, Danzo and Pain summons in recent chapters. Tsunade wouldnt have time to relese her seal and use Creation Rebirth, and even if she managed somehow, she would be still burning, so in reality, that technique is no counter for Amaterasu. The only sannin that has counter for it is Orochimaru, and thats it.