Forced to drop back two boat-lengths, the Americans couldn't recover as the Kiwi catamaran displayed impressive speed in the light winds.
Helmsman Peter Burling then compounded the penalty by further slowing down the American boat before foiling away to build a huge lead.
Emirates Team New Zealand forged further ahead on day two of the 35th America's Cup with another clean sweep of Sunday's races in Bermuda. "It's not over. We've got five days now, very important days", Spithill said.
"I think there was a clear speed advantage", said Australian Spithill, who piloted Team USA to the America's Cup in 2010 and 2013. That means they need to win eight races total to spirit the Auld Mug back to the Royal New Zealand Yacht Squadron in Auckland, where it resided from 1995 until 2003.
That break, and Oracle's ability to keep innovating proved the impetus behind the United States team's stunning comeback. Emirates Team New Zealand faces Oracle Team USA in the America's Cup sailing m. "We're obviously going to put some hours in now, really have a good look back through all the video, all the data, sharpen up and come out swinging tomorrow".
Both cartoons were drawn by San Francisco artist Elena Achilli, the first one apparently after Spithill skippered Oracle Team USA to one of the greatest comebacks in sports by winning eight straight races after being down 8-1 in 2013 on San Francisco Bay to retain the oldest trophy in worldwide sports. New Zealand are now just four wins away from the eight required to win the world's oldest global sporting competition.
The Kiwis continued their dominant form by winning both races in Bermuda on Sunday, adding to their two victories from race one and two on Saturday.
"We're under no illusions", said Burling, 26. We're just trying to keep learning and keep improving.
"On paper Jimmy Spithill has a lot of skill for that (America's Cup racing) and it's very natural for him", Groupama Team France skipper Franck Cammas told Reuters on Thursday.
Aside from how they sail and who wins the tactical battles, there are other differences that could decide victory, including how they control their wings and foils, the hydraulic systems and the way the work is shared out between the six crew.
Spithill vowed that from today to Friday the entire United States team - from boat builders, designers, engineers and crew - would be working round the clock in a bid to catch up. Simon van Velthooven, who won a bronze medal in cycling at the London Olympics, was aboard for Race 3.
Oracle made an unforced error when its catamaran came off its foils early on the downwind second leg.