While all the attention has gone to Ineos Team UK's stunning comeback in the Prada Cup, a bigger surprise has unfolded during the racing that has defied all predictions, writes Mark Orams.
The America's Cup adage that the fastest boat always wins is not ringing true – at least notyet.
Elite sport success relies heavily on good decisions under pressure, plus close-to-perfect execution. The most successful athletes, the great champions, achieve this in the vital moments.
Anything less, or at least less than your competition, means defeat.
That is what we have seen from Ineos Team UK throughout the challenger series. Simply put, they are racing better than the opposition.
Against all predictions, the three challengers' AC75s are so close in speed that the winning and losing is in the sailing. So far, this Prada Cup has been a sailor's regatta, not a design-driven boat-speed regatta.
Anyone who has watched Sir Ben Ainslie's gold-laden Olympic sailing career, which started with a silver medal as a 19-year-old, will have observed a relentlessness, even ruthlessness, unmatched in the sport.
He had a refuse-to-lose Olympic mindset. His preparation was thorough and he never hesitated in grinding the competition down by piling the pressure on them.
Ainslie is an athlete with a proven ability to make critical decisions under pressure and get them right most of the time. That pedigree is shining through in Auckland.
However the America's Cup is a team game, yet all of Ainslie's Olympic medals were in single-handed yachts. So he needed to develop leadership to match his personal talent and determination.
We have seen this leadership come through, especially during the difficult times in December's World Series when Ineos were so off the pace it was embarrassing.
Sir Ben fronted every media conference, was honest about the problems they were facing and - most importantly - within the team. He held them together and kept the team focused on improving their boat.
Tellingly, he only shared media duties after they started winning when Giles Scott fronted.
Another indication of his strong leadership came immediately after their tense, narrow final round robin win over Luna Rossa on Saturday.
The understandable jubilation from his crew after winning such an epic battle was met with a contrasting, understated suggestion of "hey guys, calm down" from Sir Ben.
He knows that no one will care who won the round robin racing in the challenger series.
His mission, their mission, is to achieve the UK's first America's Cup triumph. They want to take the Auld Mug back to the Royal Yacht Squadron where the yacht America won it for the first time in 1851.
Bypassing Sunday's scheduled final round robin race against Luna Rossa was an understandable risk-versus-reward call. Further race practice has benefits, but Ineos is on top so there were more learning advantages for Luna Rossa.
Ainslie will be keeping the foot down. He knows that while Britannia has been made much faster since Christmas, they must keep searching for more speed.
Their experience in Bermuda four years ago will be a strong reminder that great sailors still need a competitive boat.
Their AC50 catamaran was so off the pace back then they were sent packing from the challenger semifinals by an equally talented crew in a faster boat from another island nation at the opposite end of the planet.
And as good as Ainslie and his team have been, I still believe the Team New Zealand designers, and their prized yacht Te Rehutai, are the yard stick all the challengers are chasing.
That chase is, however, getting closer and the winning factor in the 36th America's Cup will be both boat speed and the ability to race at an extremely high level.