I think New Zealanders have reacted to Oracle's stunning victory in the America's Cup very well. There's very little opprobium or anger, but instead a lot of praise for Team New Zealand and respect for Oracle. A lot of people are bitterly disappointed --- hopes were, rightfully, very high when TNZ was 8-1 up --- but I don't sense the doom-and-gloom that descends whenever the All Blacks fail to win the Rugby World Cup. This is probably because TNZ was, in the long run, always the underdog, whereas the All Blacks never are.
Like Rugby World Cups, this event has been unifying for large swathes of New Zealanders. It's gratifying to know that many of your friends and neighbours, and people around you that you don't even know, are sharing this intense experience. Shared enthusiasm and disappointment, joy and despair, all contribute to building our feelings of community. This is old news: historians traditionally see World War I as a key catalyst in the development of New Zealanders' national identity, especially the ANZAC deployment at Gallipolli, which was a horrible disaster militarily.
Being much more cerebral than sportsmanly, I used to see professional sports as ridiculous and wasteful, but now I think I see one way they can be genuinely valuable. We need events, even artificial ones, to rally around. My Canadian pastor observes that Quebecois separatism subsides dramatically while the Canadian hockey team is playing during the Winter Olympics. This sort of thing forges people into nations.