Is anyone taking in to consideration that faora would not know thor is the actual god of thunder she is not from the marvel universe she has no possible way to know he is thor therefore all she knows is he is strong and he has got a hammer so my case for thor is he has the element of surprise this is what happens the fight starts and faora takes a lead in melee fighting due to her speed .But when thor decides to summon lightning she is gonna have no clue what is happening until she has been struck by lightning this not only hurts her but stuns her long enough for thor to really drop the hammer on her thus taking the win.
By that token how would Thor even know that she's superhuman until she starts beating him like a rented mule? You can't assume one knows about the other but not vice versa. And since they are fighting with morals "ON" he will be much less likely to open up big while Faora has no compunction about going straight for the throat.
Read what I wroteon top it will explain how the two characters can react without knowing each others