SAN FRANCISCO -- Suddenly, the unthinkable has entered the realm of possibility.

America's Cup defender Oracle Team USA is within striking distance of challenger Emirates Team New Zealand after two impressive victories on a beautiful Sunday on San Francisco Bay.

By winning Races 14 and 15, the U.S. team has a four-race win streak and closed the gap to 8-5 in the best-of-17 series.

"The team is getting stronger every day," Oracle skipper Jimmy Spithill said. "We made a couple of more changes to the boat last night, and it made a significant difference in terms of performance. It felt really quick. And we're not done. There are still a couple of things we'd like to get to. It was a fantastic job by the entire team."

New Zealand led this series 8-1 after winning Race 11 on Wednesday and still needs that elusive ninth victory to win the Cup for the third time.

After the first week of the 34th America's Cup, the notion of New Zealand losing four consecutive races would have been absurd. After Race 7, when New Zealand officially held a 6-0 lead (Oracle was actually at minus-1 because of a two-point cheating penalty issued before the America's Cup), Spithill tried to put the pressure on the Kiwis.

"Imagine if these guys lost from here, what an upset that would be," Spithill said at the time. "That would be one hell of a story, one hell of a comeback, and that's what I'd like to be a part of."

Now with Oracle in serious contention, Spithill is brimming with confidence and believing in his comeback dream.

"I'm not the only one," he said. "Everyone on the boat wants to be a part of it. The entire team around us wants to be a part of it. And now we've got the city and the nation behind us. People are really starting to tune in. A lot of support and messages. And just the energy down here (at Piers 27/29) is having a big impact on the guys. It's hard to put a value on that, but it makes a difference."

Sunday's races weren't exactly carbon copies of each other, but they were similar with Oracle gaining a slight upper hand at the starts and then stretching out good-sized margins on Leg 2, the first downwind leg.

"We let ourselves down on both first downwinds," New Zealand skipper Dean Barker said. "We gave up too much distance."

New Zealand would gain a bit on the upwind third leg, but Leg 4, another downwind, was tricky in both races. Wind shifts made the tacticians' jobs difficult, but Oracle's Ben Ainslie -- aided by strategist Tom Slingsby -- made better decisions and kept the Americans in front while the Kiwis ran into "holes" in the wind.

"The breeze was moving around a lot today," Ainslie said. "There were a lot of holes. The crew did a fantastic job sailing the boat and keeping it fast even in light spots. That was critical."

Oracle won Race 14 by 23 seconds and Race 15 by 37 seconds.

After losing six of the first seven races and falling behind by seven points, Oracle has rallied to win six of eight. On the scoreboard, the tally is 8-5. But in actual races, New Zealand only leads Oracle 8-7 in what is becoming the greatest America's Cup in the 162-year history of the event.

On Monday, the teams will go at it again on Day 17. That will break the all-time record for America's Cup longevity, exceeding the 16-day regatta held in New Zealand in 2003. For the Kiwis, who have been sitting on match point for four excruciating days, Monday's task is simple.

"We have to win a race," Barker said.

For Oracle, the uphill battle continues. The Americans have dealt with the loss of their No. 1 boat (which capsized in October), the two-point cheating penalty and suspension of wing sail trimmer Dirk de Ridder.

"This is a team that has gone through a lot in this campaign," Spithill said. "It was one thing after the other. But what did the team do? Didn't wave a white flag or use excuses. They've stuck with it and worked hard. It has made the team stronger.

"And now with the energy we've got and the changes we've made to the boat -- the boat is so much quicker than when we started this competition -- we believe we can win this. We believe we have the boat to do it, we have the team and we've got a wave of momentum that gets bigger every day."

34TH AMERICA'S CUP
Emirates Team New Zealand 8 points,
Oracle Team USA 5 points
Best-of-17 series or first team to 9 points
Monday: Races 16 and 17*, 1:15 p.m. and 2:15 p.m. 1 p.m. on NBC Sports Network
Tuesday: Races 18* and 19*, 1:15 p.m. and 2:15 p.m. 1 p.m. on NBC Sports Network
* -- if necessary
NOTE: Because of penalties, Oracle Team USA began the America's Cup with minus-2 points, meaning it would need to win 11 races to retain the Cup. New Zealand needs to win nine.