Lose, and Government money becomes harder to prise out of the public coffers. This year's nail-biting Cup match has been tremendous theatre but it will make the private fundraising job that much harder. One America's Cup lost campaign allows hope to burn. Two lost campaigns raises the issues in sponsors' minds of throwing good money after bad.
If Team NZ do not survive a loss, it raises the prospect that it could be some time before a New Zealand syndicate challenges again. The America's Cup will be all the poorer if the Kiwis are not there.
All of this, of course, has yet to be determined and Team NZ can still win the Cup. They still need the same recipe - and are still perfectly capable of following it: predict the weather perfectly, mode the boat perfectly, win the start, be first to the bottom mark, cover the opposition's every move, sail perfectly.
That's a lot of "perfectlys" but this is a team capable of perfection.
But that one race is proving chillingly elusive. More and more, it seems they need Oracle Team USA to make a mistake or ETNZ need the lucky break that deserted them when the abandoned Race 9 was called off because Team NZ - ahead by over a kilometre - couldn't make the ridiculous 40-minute time limit in the light winds that applied that day.
The luck isn't with them right now. Neither is the boat speed.
Oracle discovered the dreaded silver bullet - how to make their boat go faster.
On September 14, in the Weekend Herald, I wrote: "It will take an accident, a breakage, a miracle of boat engineering or an act of God. Barring that, team New Zealand will win the 34th America's Cup."
Well, they did it. Oracle found a miracle of boat engineering. Somehow they have achieved the following:
# They are now quicker to get up on their foils than ETNZ
# They foil for longer periods, more stably
# They are demonstrably faster on the first reaching leg - setting them up in control of the races
# Jimmy Spithill has, for the most part, outdone Dean Barker at the starts
# They have a slight edge downwind
# They have eradicated their boat handling errors
# They are picking the weather, moding their boat and finding wind and tide advantages on the water better than Team NZ is at present.
Team NZ still have an edge upwind - until race 18, anyway - but Oracle have so radically increased their all-round speed that they are no longer Team NZ's upwind bunnies, as they were earlier in the regatta.
The Kiwis are not sitting still. They are trying to re-jig their boat too, every day, every night. But the huge gains they made in boat speed earlier in the regatta seem to have reached a plateau. Either that or Oracle have been able to copy their gains and add their own.
ETNZ's foiling ability, compared to Oracle's speed and stability right now, suggests that they may have sacrificed a little bit of stability in the search for extra speed. So did their throwing up of a code zero sail in race 16 - maybe an attempt to find, from anywhere, that little bit of extra speed they crave to pick off that one, final, enticing race.
But that will have to wait now until tomorrow when winds for the racing are predicted by regatta director Iain Murray to be "fresh to frightening".
Losing is a frightening prospect indeed.