He had opened the man-wound! A minute before Thor had been fighting for law and right--without great animosity or serious desire to kill.

Now, however, he was terrible.

His mouth was open, and it was eight inches from jaw to jaw; his lips were drawn up until his white teeth and his red gums were bared; muscles stood out like cords on his nostrils, and between his eyes was a furrow like the cleft made by an axe in the trunk of a pine.

His eyes shone with the glare of red garnets, their greenish-black pupils almost obliterated by the ferocious fire that was in them.

Man, facing Thor in this moment, would have known that only one would come out alive.
Thor was not a "stand-up" fighter.