Battling Oracle performance closes America's gap to four points.

Image credit: Gilles Martin-Raget/America's Cup.

34th America's Cup defenders Oracle Team USA battled their way to another race win this morning in San Francisco to take the scoreline to eight races to four against Emirates Team New Zealand and keep their precarious defence hope alive.

With the right hand side of the racecourse shrouded in fog this morning, the backdrop for this latest match up could not have been more dramatic. 

There was little engagement in the prestart and the boats started pretty much level with the Kiwis crossing close to the right hand buoy on the line and Oracle a few boat lengths to leeward. 

Oracle did a great job of getting up to and maintaining maximum speed to prevent ETNZ to be able to roll over them. OTUSA helmsman James Spithill luffed his rivals way high of the first mark to ensure he would have them directly behind when they gybed near the left hand boundary off the shoreline.

New Zealand did a slow gybe - possibly deliberately to avoid becoming overlapped in the three boat length circle - and this allowed Oracle to get up and running quickest and extend their lead in the early part of the run. 

This trend accelerated at the bottom of the leg with the American boat sailing marginally better VMGs and they rounded the right hand leeward gate mark 24 seconds ahead. The Kiwis split to the left mark and tacked shortly afterwards to follow Oracle towards the Cone of Alcatraz tidal relief.

Each boat gained and lost as they sort tacked to stay in the cone; Oracle looked focused on keeping a loose to medium cover on ETNZ.

But when the two teams first started the long starboard tack over towards San Francisco Oracle seemed to be in control, but as the breeze began to drop on the approach to the shore Oracle began to look a little stick and the New Zealand boat began to make gains.

Two crosses later there was nothing in it with the Kiwis on port crossing close to the American boat's stern.

Oracle tactician Ben Ainslie held his nerve however and broke off from covering to send the black boat out on a long port tack out towards the middle of the race course.

When ETNZ followed they appeared to be making steady gains as the breeze began to clock to the left, setting up a nail biting approach to the windward gate. 

So far this Cup the right hand gate mark has proved the most favourable and Oracle on the right clearly did not want to hand this advantage to ETNZ and were willing to sacrifice speed for positioning to lock out the New Zealanders. 

Tacking just before the starboard layline to the right mark they crossed the Kiwis and then tacked again for the right mark. Although that meant ETNZ could make a smoother faster rounding at the left mark, ultimately the previous left hand shift meant when Oracle gybed on to port they were quickly off and running and sailing fast on the paying gybe.

The Kiwis meanwhile struggled to get themselves out of the left hand corner and the delta to Oracle grew instantly to over 300 metres.

However the patchy conditions meant that Oracle were far from home and dry. Shortly after the half way point of the run they sailed into a patch of lighter winds on the left of the course and when they slowly gybed back they were almost pointing back at the ETNZ boat which was ripping along on port gybe. 

Oracle scraped across in front though and made another slow looking gybe to block off the Kiwis.

A slow gybe turn from Emirates Team New Zealand then threw the advantage back to Oracle however as now the Kiwis were sailing in lighter winds. 

The lead compressed and extended twice more before Oracle finally gybed clear ahead and headed for the final leeward turn mark and relievedly headed for the finish.

Scoreline now eight to four in favour of the Kiwis.

What would the final race of the day hold for the two teams.