Twisting seems to be the inherant nature of some jersey fabrics, particularly with the single jerseys. I think it's probably down to the way the fabric is knitted and one side of each stich is minutely smaller than the other side of the stitch, nothing in itself but thousands of stitches add up. We all know what RTW tee shirts can be like.
Pre-washing should release any superficial tensions, but after that I think that you will probably get better results if you fold the fabric lengthways on grain, in line with the vertical columns of stitches and let the rows do their own thing. Of course if it's a striped fabric you have to go with the stripes. Pressing and agressively forcing it into square won't work, it will just twist back again as soon as it's washed.