Oracle Team USA are turning the screw on Emirates Team New Zealand, bringing more intensity to the victory that just will not arrive.
That could lead to more frustration today.
Oracle last night turned down a proposal from organisers to adapt the race course for some unusual weather. The weather gods predicted a front passing through San Francisco overnight, bringing rain and possibly high winds. However, as with all fronts, it is difficult to predict what weather will apply during and afterwards.
It could blow like a tempest or be reasonably settled. Either way, it may be difficult for the teams to set up their boats for maximum effect.
It's also likely to be a long way away from the light airs in which Team NZ trounced Oracle Team USA before the time limit intervened yesterday.
The teams do know the wind will be unusual - in that it will come from the south.
That led organisers to try to alter the course to take account of the likely wind direction. However, Oracle apparently declined.
It's thought they believe they will do better in such conditions and, even if the weather intervenes and delays more races, the forecast is for higher winds later in the week - which would play to Oracle's strengths.
There were reports last night of an extended period being agreed upon to get a race under way but that will not be known until this morning. That would lessen the chances of a race being postponed because of wind limits as the organisers would have longer to let the winds settle into race mode.
But it is not a promising omen for a regatta that began as a Team New Zealand stroll to victory down a path littered with flowers but which now appears to have more than a touch of a blizzard-strewn Everest about it.
The frustration is beginning to show in Team NZ. They still have the power of the percentages behind them. One bad mistake by the opposition and the Cup will be theirs.
But it is not Oracle making the mistakes at the moment and they seem to have an edge in boat speed in most winds at the upper end of the scale.
In the lowest winds of the match so far - 9 knots - Team New Zealand opened up the widest margin of the Cup match (about 1.5km) in destroying the Oracle challenge. Then they were tripped up by the time limits. Every race has to be completed within 40 minutes or it is called off.
A worried Dean Barker, the Team NZ skipper, glanced at his watch on the second downwind run and realised they were not going to finish in time.
Famously controlled in manner, Barker said: "This is the third race now we've been in the lead and haven't won either due to hitting the wind limits or today the time limits, so you sort of say any one of those three points would have been quite nice right now."
Later, asked about the wind limits, he said: "It was very frustrating to have it [the race] blown off."
For Barker, that is practically having a tantrum. Asked about the wisdom of having minimum wind limits of 5 knots when a race with winds of 9 knots could not even be finished in time, he said: "That's not going to work if you start a race in 5 knots; it would be very difficult to make it work."
Ray Davies, Team NZ's tactician, was also testy when asked if Team NZ needed luck to win the America's Cup.
"Luck beats skill every time," he said archly, but with the trademark Davies grin softening the sarcasm.
"Obviously the odds are firmly in our favour at the moment and we've just got to go out there and execute a day like we did in the first race.
"To get 1km ahead was pretty good. We've just got to go out there with the same sort of intent [today]."
That response may also have been spurred by yet another gung-ho response by Oracle skipper Jimmy Spithill.
"You dodge all sorts of bullets in these boats on that course," he said when asked if his team was saved by the time limits.
"But I think back to the start of this regatta when, four days before, we were fined, docked two points and we lost our wing trimmer.
"This feels to me as if the tide is starting to turn and we are really starting to build something.
"There is so much support from the people of San Francisco and that is affecting the whole team. The tide is turning and it's starting to go our way."
But Team NZ have been winning their share of races.