Earlier, Team NZ steadied the nerves, after the Americans captured their first victory yesterday.
Victory for Team New Zealand would cap Ashby's stunning sailing career that already includes multiple world championships and an Olympic silver medal.
In the second race, Burling out-foxed Spithill in the pre-start box to hit the start line a mammoth 14 seconds in front - appearing to offer a wave to the rival crew.
Team New Zealand, the hard-luck loser to Oracle in 2013, gained during a wind shift on leg four of the sixth race and passed Oracle in the matchup of 50-foot foiling catamarans.
In 2013, Oracle trailed Team New Zealand 8-1 on San Francisco Bay before winning eight straight races to complete one of the greatest comebacks in sports.
Spithill was out-sailed by hotshot young Kiwi helmsman Peter Burling on Sunday and as the pressure mounted on the defenders their mistakes multiplied.
"It makes life a little easier when you get off the start 14 seconds ahead", said Burling, who some thought would struggle when matching wits with two-time Cup victor Spithill.More news: Verizon deal closes, CEO Marissa Mayer resigns
Because Oracle won the qualifiers, the Kiwis started this America's Cup match on the Great Sound with a negative point. "I expect the Minister of Sport Jonathan Coleman to be in discussion with them should we win". We're in a tough situation now and all we can really do is take this one race at a time.
"That was important", Spithill said.
"We all saw today that the boat was faster".
"We didn't sail particularly well today but it was great to walk away with another win". On leg three there was very little between the two teams but the Kiwis extended their advantage again as they headed upwind, giving themselves a 32 second lead as they headed into leg four.
But although the New Zealanders got away, the United States champions recovered well and fought their way back into the race, finding the speed which had evaded them in previous encounters. "We're really excited about being able to go out there tomorrow and put it all on the line again".
"We've got a pretty impressive bunch of designers in the chase [boat], tweaking it and making sure our starting package is as good as it can be", said Burling.
The next time the boats came together, Team New Zealand was slightly ahead and on favored starboard tack.
Both crews were out practicing ahead of the racing, skimming over the crystal clear waters of the natural sailing "arena" that made Bermuda a favourite location for the competition.