Morale, the will to fight, is, in fact, the will to win, or at least to reject losing. Whenever you are in a situation, a game of chess, for example, you will generally have a pretty good idea of when you have ultimately lost. Even if the finishing move is not for many more moves. You still have a sense deep in your gut that you have lost. This, in turn, reflects how you play the rest of the match. Immediately, your game, depending on your disposition, of course, will go on the defensive or is in some way resigned to your fate. You may fight a little longer, but it is no longer with the expectation of victory.
At the same time, it is often the case that you can also sense this resignation, the breaking of the will, in your opponent. In Brazilian Jiu-Jitsu, for example, one can often feel the opponent’s will break. You can sometimes literally feel the fight go out of them as they resign themselves to the loss.
From this information, you can gather at least two things: a strategy for victory and a strategy for defeat. The late-great military historian John Keegan stated that the usual metric for military victory was the number of prisoners. War, in a sense, can be boiled down to beating your opponent enough, terrifying them enough, to get them to give up. The country of Luxembourg lost only 17 men in WWII before it opted to surrender. France, who had withstood the might of Germany for years during WWI, crumbled in weeks. While it is true that Luxembourg is tiny (with modern-day Luxembourg only having a couple of hundred of thousand people) and France was defeated through their own incompetence and superior German tactics, the point still stands. They lost the will to fight.
Thus, the importance of morale. You have to believe that you not only can win but that there is a purpose or reason for you to win. The former is the hope of the inferior force, while the latter is the hope of the superior force. These hopes, or lack thereof, can make or break a chess match, a basketball game, or a war (conventional or otherwise). This is all to say that your mindset is important. And that, more importantly, you need to have hope to have the will to fight.