The fight is expected, but Thor doesn't even flinch for every time a hand lashes against him and aims true. He can hardly feel it at this point, he's cold and numb and there are things more painful than a haphazard strike to the face.

Once he has slammed Bucky's head an adequate amount, he shoves his head further downward into the water. The chill of the water bites at his hand painfully, but again it's a small price to pay when he's so close to victory. He hardly needs to do it at this point, but he needs to be sure Bucky is dead.

His hands press in deeper, careful not to tip himself in when he does, waiting for Bucky to go limp before he starts to push him into the water.