They say imitation is the sincerest form of flattery, so Team New Zealand take it as a compliment that Oracle Team USA have been copy-catting some of their strategies and manoeuvres.
Other than making significant strides with their upwind performance, particularly in heavy air, one of the reasons behind the Oracle team's sudden improvement is they have learned to get the boat around the racecourse better.
During the early races, skipper Jimmy Spithill mentioned on several occasions they were struggling to match Team New Zealand's efficiency with their tacks. The Kiwi crew were gaining a lot of ground early on as they were able to perform a hull-to-hull tack - when the boat rolls from one hull to the other in the tack, limiting the wetted surface area in the manoeuvre. The Oracle crew have spent a lot of time studying Team NZ's choreography of this move and have begun executing it themselves. Oracle also seem to have copied Team NZ's upwind foiling technique, where their hulls skim the water, rather than full foiling mode, which is faster but less stable.
Team NZ skipper Dean Barker said given Oracle haven't really had the luxury of racing their boat in proper match race conditions until now, they were always going to pick up a few things as they go.
"We've been in a race environment for a lot longer than they have, so we probably learned things a little bit earlier than they did," said Barker. "If there's good ideas out there then you obviously try your best to match them and they have obviously had a good look at what we've been doing, they've simulated a lot of those and it's working for them."
Barker said just as his team improved at an exponential rate during the Louis Vuitton series, he always expected his opponents would get better as the America's Cup match wore on. But he remains confident in the performance of the Kiwi boat.
While Oracle's drastic changes come with big risks, Team NZ continue to make subtle improvements to their boat.
"We're refining the whole time. Every day we learn a little bit more about how to sail the boat consistently better, just in the moding and how quickly you accelerate out of tacks and everything else and you've just got to keep pushing the limits of that," he said.