They have done better at reading the conditions and moding their boat for them.
Their boat handling has improved markedly - but then boat handling and tactics come more easily to he who has the faster boat.
The real revolution has come in Oracle's ability to foil quickly, to maintain that foiling longer than Emirates Team NZ and to do so more stably. That, and a marked increase in their acceleration, is what has turned the America's Cup match around.
In the earlier part of the regatta, all that could have been said of the New Zealand boat.
Oracle have so far not divulged anything about the improvements made to the boat but may be prompted to explain today, win or lose.
There are all sorts of theories flying round the sailing community, including a suspicion that Oracle have somehow got some sort of power-assisted dimension into their boards system and through the measurers' scrutiny.
But skipper Dean Barker deflected such questions yesterday and gave his clearest signal yet that Team NZ are struggling to foot it with Oracle's new speed: "You have to give credit where credit is due. Their guys have sailed incredibly well. That second race was phenomenal; it was shy of impressive, quite amazing. they have done an amazing job."
But while that sounded to some as if Barker - who has played a very straight bat to all probing questions in this regatta - was running up the white flag, he came back on course: "I know we can win. I know we have been saying this for a few days but I have an absolute belief in this team and will go out and give it our best shot."
Asked whether, in Race 18's decisive moment, the Kiwis should have handled the key tack better in the upwind leg, Barker said: "There are things we could have done better. It was fairly clear to see that we could have tacked about anywhere - they were going pretty damned well.
"For the first time we recognised we were not as strong as we needed to be. It was tough - the guys never gave up but the Oracle guys were going pretty well in that stuff [20+ knots of wind]."
Barker admitted that his starting had cost them the race in Race 17 when he copped two penalties as the two giant AC72s tangled in the start box, colliding softly.
Barker had a good position but was found to have fouled Oracle when to leeward - and suffered another penalty for not clearing the way quick enough. Team NZ acknowledged they had not done a good enough job of clearing out of Oracle's way but felt the first penalty was harsh.
" I did a really bad job at the start," said Barker. "It really put us on the back foot and took us out of the first race at the start. In the second race, we executed everything well in the first part of the race and we still got beaten in the end.
"That is all that you can ask of the guys - put everything in and never give up. We got beaten and it is tough to handle but sometimes you have to accept it."
You fear a bit for Barker if Team NZ don't miraculously win. The Kiwi clobbering machine is particularly harsh on fallen heroes - and this regatta has looked like Barker's time before Oracle performed the turnaround.
He has come second to Oracle skipper Jimmy Spithill in the starts but the start has only been one element of this match. This has been about boat speed and technology, first and foremost.
Keeping trim for the next challenge or defence
Once the America's Cup is done and dusted, we're going to need a breather. Here are four ways to put the event behind you.
1. Catch the musical Wicked
The wildly successful musical, based on the 1939 movie Wizard of Oz, is playing at the Civic for a limited run.
2. Watch Liverpool play Southampton on TV One
The English Premier League is currently being shown on TV One at noon on Sunday.
3. Reach for the stars in Alfonso Cuaron's Gravity
Hailed by some critics as the film of the year, Gravity which will put you on the edge of your seat.
4. Read J.K. Rowling's new crime novel
Released this year, The Cuckoo's Calling has become a bestseller since the author was unmasked.
