this phrase gets used to explain why one team prevailed and another team failed. personally, it always felt like a cheap cop-out answer to me. it's a way of diplomatically 'explaining' the victory without saying anything bad about the other team. but I've know quite a few people who play sports who actually believe this to be true.
if somebody explicitly stated how and why they won that might be considered offensive and unsportsmanlike. especially if this means pointing out blunders or failures on the other team. so the cop-out answer is a good way to 'answer' the question without being too offensive.
now, I'm not big into sports. I'm a student of military history-- so my natural reaction is to think that the 'will for victory', in and of itself, is not sufficient to secure the desired victory. you could want something demonstrably more than your enemy and STILL lose because you lack the administrative abilities, coordination and communication, and resources to triumph over your enemy. case in point... during the Polish Uprising nobody wanted to win MORE than the Poles in Warsaw. but once the Allies made it clear that they wouldn't support them in their combat with Germany their defeat was inevitable.
back to sports... I could see the whole 'willpower' and 'wanting it more' being a thing for boxing, mixed martial arts, or endurance based sports like marathons... but for highly coordinated team sports it's just hard for me to buy into that line of argument.
so... what do you guys think. "we just wanted it more." is a good enough explanation or not?