america's cup
There will be two races on Tuesday, and could continue on Wednesday and Thursday. Reuters

Oracle Team USA and Emirates Team New Zealand split two dramatic races on Sunday, winning one each in heavy winds on San Francisco Bay and sending the America's Cup sailing regatta into a tense and unexpectedly close final week of competition.

The second race was among the most thrilling in America's Cup history as the two teams changed leads four times, dueling neck-and-neck for much of the course before New Zealand eked out a 17-second victory.

"If you didn't enjoy today's racing you should probably watch another sport," New Zealand skipper Dean Barker said at a new conference afterward.

New Zealand won a very close start and barely maintained its controlling inside position against a faster Oracle around the first mark, before slingshotting to a lead. Oracle made a poor turn rounding the second mark, but steadily gained ground on the upwind leg - as it had done in the previous two races - putting the duel into a dead heat at the third mark.

On the final downwind leg, Oracle skipper Jimmy Spithill had to steer behind the Kiwi boat as the two 72-foot catamarans converged, but he slowed too much and made a longer turn, allowing New Zealand to sail away to the win.

Despite the second-race loss, Oracle showed again Sunday that changes it had made to its boat after losing six of the first seven finals races, combined with much-improved tacking, had closed the speed gap with New Zealand.

"You are constantly learning," said Oracle skipper Jimmy Spithill. "This is the most we've learned, lining up against these guys. Even after today we have a heap of stuff we'd like to do with the boat."

In the first race Sunday, Oracle won the start and stomped on the gas pedal in the initial run with the wind. It opened up an 18-second lead and then showed a significant speed advantage on the upwind leg to all but seal a 47-second victory.

Oracle tactician and British Olympic gold medalist Ben Ainslie afterward said it was "the most fun and exciting sailing I've ever been involved with - to see these two teams get a grip on these boats and what they are capable of."

After its second-race win, New Zealand led the competition seven races to one, with Oracle's first two wins having been negated by a cheating penalty before the finals began. The first team to score nine points will take home the 162-year-old America's Cup trophy.

Until Oracle's win on Saturday, New Zealand had dominated the competition with superior tacking and upwind boatspeed. New Zealand trounced challengers from Italy and Sweden to gain the right to take on defending champion Oracle in the finals.

The wind exceeded 20 knots (23 mph) for both races, hold just under the maximum allowed for Sunday's competition, held on a crystal clear day on the Bay. A big crowd was on hand for the newly-competitive event, which the previous day drew 52,000 to viewing areas along the waterfront.

Sunday's wild racing was a vindication for America's Cup organizers, led by software mogul Larry Ellison, whose decision to use extremely expensive and sometimes-dangerous high-tech catamarans for the competition has been widely criticized.

A dearth of challengers, a cheating scandal, a fatal accident and many weeks of one-sided racing had threatened to make a mockery of the event.

But the spectacle of the huge carbon-fiber boats hurtling across the Bay at 50 miles an hour in razor-tight races, with good shore viewing and sophisticated TV coverage, is exactly what organizers hoped would ultimately drive interest in the event.

The competition is scheduled to continue with two races on Tuesday and, depending on the results, will continue on Wednesday and Thursday.

(By Jonathan Weber)