KEY POINTS:
Alinghi have bounced back and it is 2-all in the America's Cup match in Valencia
The Swiss played the oscillating breeze to perfection to level the score in race four.
In a race where securing the wind shifts and pressure was essential Alinghi lead over the start line and around each mark winning by a comfortable 30 seconds.
However, shortly after the race Emirates Team New Zealand said it had lodged a protest with the America's Cup jury over Alinghi's mainsail locking system, which it said breached the class rule.
The rule stated that the mainsail had to be able to be lowered to the desk without a crew member having to go aloft. The hearing begins at 11am (9pm NZ time).
On the water, there was nothing between the two boats. The race was won on boat positioning.
The score is now 2-all in the best of nine race series. There is a now a lay day before race five on Friday night (NZT).
In a conservative start both sides appeared to secure the sides they wanted. Alinghi started to the right and trimmed up to perfection powering over the line at pace.
Team New Zealand started to leeward and the two sides headed off on a massive drag race out to the left and to the layline.
With the breeze swinging between the two sides Team New Zealand tactician Terry Hutchinson told his team "It is a long race boys, keep it cool."
Nearing the top mark Alinghi were the first to tack off which Team New Zealand followed shortly after.
At the top mark the defenders held a comfortable 20 second lead. Team New Zealand immediately attacked on the downwind run.
But after performing a flawless gybe set round the mark, Team New Zealand's fans watching in the 'wool shed' in Valencia were left gasping when Team New Zealand's giant red spinnaker got a twist in it mid way down the run which allowed the Swiss to ease further ahead.
But as has been the case in this series so far Team New Zealand clawed their way back. The Swiss sailed into a millpond at the bottom gate, which drew applause from the 'wool shed' as the black boat came swooping in.
But despite their downwind efforts, Team New Zealand trailed the Swiss around the gate by 34 seconds.
Up the second beat the game was equally as intriguing as Alinghi surged ahead and New Zealand charged back. Having learnt from the previous two races where they were perhaps a little guilty of playing it loose tactically, the Alinghi afterguard never let the black boat out of their sight.
The Swiss sailed a very nice second beat in the tricky conditions to round the final mark 24 seconds ahead.
Down the final run Team New Zealand threw gybe after gybe at the Swiss but the Swiss extended to win comfortably.
However the measurer immediatly boarded the swiss boat to check the halyard lock at the top the mainsail.
- additional reporting NZPA