How did Jor-El stand a chance against Zod?

Just because Jor-El was a nerd doesn't mean he is a weakling. Jor-El is a skilled fighter and pilot in the comics.

It doesn't matter what skills they possess, because in that scene you can see that Zod was surprised to see Jor-El do something so drastic. Zod was naive, in my opinion, even until the climax. He actually thought Kal-El would somehow give up on the earthlings. He says during the climax fights that his entire race is all gone, quite emotionally.

My point is, when he sees that Jor-El is ready to go the distance, he is surprised and that's when Jor-El gets him - while Zod is off-balance. He wouldn't be able to do that in an open situation, granted.

And what about the other scene when Jor-El escaped while being captive. He takes three guys using only a flash as the distraction. Jor-El is pretty bad-ass and this scene was kept for a reason - to clear your specific doubt. Jor-El was very skilled at fighting but not as good as Zod.

I don't agree with you, he did not completely demolish Zod. Zod was just down for a minute and the launch was done. It was unfair really. Two against one. One working the launch and one fighting Zod.