It was a day of big gains and big losses as Oracle sailed through to win both races of Day 12 of the America's Cup.

Team NZ came so close to overtaking Oracle on at least four occasions but Oracle managed to slip away.

Both starts were even but Oracle was able to luff NZ wide at the first mark forcing Dean Barker and crew to play catch-up.

They threw attack after attack in both races; harried and put on the pressure twice closing the gap from 300m to almost zero and once from 700m.

Oracle won by 23seconds in race 14 and 37seconds in race 15.

Barker said it was always going to be a difficult day with big variations in wind at the top and bottom of the course. It was patchy and there were a lot of shifts. Two starboard start-box entries didn't help."

Barker said Oracle sailed really well, managing the first downwind legs well, establishing good leads.

"We gave them opportunities we should not have done. We fought back, got close at times, but it was Oracle's day."

Emirates Team New Zealand sits on match point, needing one win to take the America's Cup. Oracle needs to win four more.

Standings (first to 9 points wins)

Emirates Team New Zealand – 8

ORACLE TEAM USA – 5

Race 15 performance data

Course: 5 Legs/10.22 nautical miles

Elapsed Time: OTUSA – 27:34, ETNZ – 28:11

Delta: OTUSA +:37

Total distance sailed: OTUSA – 12.0 NM, ETNZ – 11.9 NM

Average speed: OTUSA – 26.23 knots (30 mph), ETNZ – 25.40 knots (29 mph)

Top speed: OTUSA – 41.80 knots (48 mph), ETNZ – 40.35 knots (46 mph)

Windspeed: Average – 12.9 knots, Peak – 18.0 knots

Number of tacks/gybes: OTUSA – 7/7, ETNZ – 7/9

Race 14 performance data

Course: 5 Legs/10.22 nautical miles

Elapsed time: OTUSA – 33:47, ETNZ – 34:10

Delta: OTUSA +:23

Total distance sailed: OTUSA – 12.8 NM, ETNZ – 13.1 NM

Average speed: OTUSA – 23.31 knots (27 mph), ETNZ – 22.58 knots (26 mph)

Top speed: OTUSA – 36.60 knots (42 mph), ETNZ – 35.41 knots (41 mph)

Windspeed: Average – 11.4 knots, Peak – 14.9 knots

Number of tacks/gybes: OTUSA – 8/12, ETNZ – 8/12

Earlier:

Wind conditions for today are favourable with a breeze expected to build from 10 to 20 knots during the day. With an incoming tide, that will take the wind limit out to 24.4 knots for the first race and 23.3 knots for the second race.

A whale spotted in San Fransisco Bay. Photo: You Tube.

The teams: Emirates Team New Zealand: Skipper/helmsman: Dean Barker (14), Tactician: Ray Davies (10), Wing Trimmer: Glenn Ashby (3), Trimmer: James Dagg (9), Bow: Adam Beashel (2), Pit: Jeremy Lomas (8), Pedestal 1: Chris Ward (7), Pedestal 2: Rob Waddell (11), Pedestal 3: Winston MacFarlane (4), Pedestal 4: Chris McAsey (5), Float/Grinder: Derek Saward (12)

Oracle Team USA: Skipper: Jimmy Spithill (9), Tactician: Ben Ainslie (12), Strategist: Tom Slingsby (10), Wing trimmer: Kyle Langford (8), Jib trimmer: Joe Newton (5), Off-side trimmer: Rome Kirby (4), Grinders: Shannon Falcone (1), Joe Spooner (2), Jono MacBeth (3), Gillo Nobili (6), Simeon Tienpont (7)