"Duking it out?" Seriously? On the basis of the first week sales of Mario Kart? At best, the Wii U will see a sales bump for maybe 2-3 weeks. After that, the remainder of 2014 will probably be best described as the PS4 beating the Wii U over the head from bell to bell.
Don't agree? Just take a look at the sales projections from Nintendo and SCE.