Perhaps the major revelation from the weekend's racing in the America's Cup was the upwind speed of Emirates Team New Zealand.

In Sunday's clash with Luna Rossa, the first two-boat race of the regatta, the New Zealand team surprised, not only with the scale of their defeat of the Italian challengers but with their speed upwind.

Downwind speed was expected of Team NZ and Aotearoa, their Mark II 72-foot AC72 catamaran, as the Kiwis have led the way in foiling and in gybe foiling - one area where they have got the jump on the America's Cup field so far.

However, it is not possible to assess comparative boat speeds until the big cats face each other - and it was then that the upwind prowess of the New Zealand team revealed itself.

Team NZ have always said their original boat design meant they were highly competitive downwind but might be surrendering time upwind to the likes of defenders Oracle.

How much time and whether it would be significant is one of the questions on which this regatta may turn.

However, against Luna Rossa, Team NZ were only marginally faster downwind but ran away from the Italians on the upwind legs - not what most pundits were expecting.

Team boss Grant Dalton was, however, not getting carried away with their upwind performance.

"I thought we did sail very nicely upwind," he said. "But don't be fooled. The time flattered us and I don't think you'll ever see that [a spanking like the Italians got] again.

"The thing is that we got away on them at the start and were able to blow right over on the tide. It left them picking up the scraps, really, and it's very difficult if you are behind at the bottom mark and you shut the door on them like we did - it's a pretty brutal racecourse that way."

Asked if the upwind improvement was down to structural alterations - like biasing the hulls more towards upwind rather than downwind - Dalton said: "It's a combination. These things aren't like a monohull where you are digging a bit of a hole in the ocean. They have such low drag.

"They are so efficient that, when you start making aerodynamic gains, they become exponential, create more wind and go faster again. You find that what was a 2m gain has become a 30m gain."

Dalton pointed out that the Italians had not sailed well - their gybing was not great - and that they would improve significantly.

"So it's been a raft of small changes which, because of the nature of these things, turn out to be big gains when you sail them right. On paper, the hulls [on the second boat] are very, very similar to the first boat.

"If we'd made the changes we have made to the first boat, it would be a much quicker boat upwind as well."

Meanwhile, Team NZ are counting down the days until they qualify for direct entry to the Louis Vuitton final, which starts on August 17. They will go into a best-of-13 races final if they win the round robin - which looks a foregone conclusion without other challengers. That mark is likely to be reached on Monday when they race Luna Rossa again and, barring accident, a win should mean a finals berth.

Dalton said the team were looking forward to it because they needed to get back into the development programme for the boat.

"We plan to start going back into development," he said. "Because of all these safety changes that needed to be made [after the death of crewman Andrew Simpson in the Artemis capsize two months ago], that sucked up all our human resources. That halted our development programme.

"So we are so far behind our own schedule - I reckon we are close to a month behind - that we need to catch up and if we can qualify for the final, that will help give us the time to do so."

Artemis back in murky waters over rudder ruling

It is beginning to look like the attempt to help Artemis, the wounded challenger of the America's Cup, to get to the start line with special rudders may not happen.

Regatta director Iain Murray said yesterday that he would chair a meeting today of all teams, their engineers and designers, to hash out (among other things) whether Artemis would be allowed to race with rudders outlawed by a recent jury decision.

Some seasoned Cup observers think the Italian syndicate Luna Rossa vetoing the idea will eventually relent and permit the rudder changes.

However, there is no shortage of bad blood between the Italians and the Swedish team after Artemis challenged Luna Rossa over their design co-operation with Emirates Team NZ and in exchanges in the jury room.

The proposed rudder changes are, ironically, exactly those which were the subject of successful protests from Luna Rossa and Team NZ. The protests claimed that rudder changes proposed by regatta director Iain Murray under the banner of safety could not be pushed through without the consent of all teams; they were also said to be performance-related rather than safety measures, unfairly advantaging holders Oracle.

After winning the protest, Team NZ then suggested giving Artemis dispensation from the class rule, if the proposed rudder changes were vital for their participation. That opened the door for the Swedish syndicate to compete, laying to rest their earlier threat to withdraw if the protests were upheld.

Murray, however, sounded bullish yesterday about the prospect of Artemis getting their new boat in the water and racing: "They have about a week's work before getting the boat in the water and they could even be working on their initial outing as soon as next weekend."

Murray said they finished their rigorous structural testing yesterday and was "sure they came through with flying colours".

The Artemis crew will have little time to experiment and learn before they are due to compete in the Louis Vuitton semifinals on August 7.

Most expect Artemis not to be competitive so the offer from Team NZ is good for the regatta in that it attempts to get a third challenger to the start line; even if it survives the Italian veto, it is not expected to make any difference to the anticipated pecking order.

That sees Team NZ going through to the Louis Vuitton final with Luna Rossa and Artemis duking it out to find the finals opponent. Most already believe that will be Luna Rossa, whether Artemis starts or not.

However, it is possible to see this from the Italian point of view. Although they will have sailing matters on which they can improve, they were so soundly beaten by Team NZ on Saturday that they finished more than five minutes behind and were officially listed as Did Not Finish.

They will wish to salve their wounds by making sure they make it to the Louis Vuitton final - and not a syndicate they helped by bending the rules over rudders.