Here is the situation:
Loser uses his power to declare an upset, but he only has a Negotiate card, so he plays it. His opponent plays an Attack card, so the Loser loses, and thus wins. (With me so far?) Now, since the opponents ships went to the Warp, does the opponent get to take compensation? My instinct says no, because the opponent did not actually play a Negotiate card, and is thus ineligible for compensation. And the Loser does not take compensation, because none of his ships were sent to the Warp.