This is thor in character. So basically its Flash vs a brawler. A slow Brawler at that. If this isnt over in a second or two im seeing thor trying to register what the heck is going on and trying to use simple wind or maybe him spamming lightning everywhere since he wont be able to even see flash. obviously that wouldnt work as lightning is much, much too slow to hit flash. then after that it'd be over. I honestly cant see this lasting more than 3 seconds.
Thor should be able to perceive Flash, hitting him in motion seems completely unlikely.
Wait he can?