Emirates Team New Zealand won its first semi-final match on Tuesday beating Desafio Espanol by 43 seconds.

The match finished dramatically. Two thirds of the way down the second downwind leg the wind shifted massively; NZL 92 dropped its gennaker and raised a genoa and finished the leg on the wind.

ESP 97 held on for a couple of minutes, had to drop the gennaker when they could no longer hold it and then cut it free when they could not retrieve it.

In the other semi-final match of the Louis Vuitton Cup, Luna Rossa beat BMW Oracle by 2min 19 sec.

In the semi-finals the first yacht to win five races goes through to the final.

Racing was held in a 10 - 19 knot breeze that was very shifty and tested afterguards, time after time. That big wind shift: at the second windward mark the breeze was 13 knots from 255 deg, at the finish it was 8 knots from 92 deg - a shift of around 160 degrees.

For NZL 92, the game plan was to pick the shifts and work them. Once in the lead the plan was to play a conservative game to protect the advantage. With large wind shifts, the danger is always that the advantage can swing quickly to the opposition.

NZL 92 got away to a clean start and took the right of the course. On that first beat, the shifts went NZL 92's way; on the first downwind leg ESP 97 managed to eat into NZL 92's lead to take 22 seconds out of the delta at the second mark.

On the second beat NZL 92 stretched at first, ESP 97 came back and were within two boat lengths then NZ 92 played a sound tactical game on the approach to the mark to round comfortably.

Grant Dalton: "The breeze was really tricky today, but the weather team and the afterguard were on top of it and the boys responded with a great performance.

"Spain sailed a really good race. They gave us no breathing room and several times they took worrying chunks out of our lead and then we got another shift and we were away again.

"That last run was bizarre and shows just how tricky it was and we could see that shift coming and dropped the gennaker before we got into trouble.

"In the end the margins looked comfortable but it was very tense the whole time."

The margins: at the first windward mark 1min 03sec, first leeward 41 sec, second windward 30 sec and at the finish 43 sec.

Wednesday's weather: South-east breeze 10 - 14 knots, 13 - 25 deg, 50% humidity, sun.