Defenders Oracle Team USA continued their big comeback in the America's Cup, after a disastrous start by Team New Zealand allowed them to sail away to their sixth victory in a row.

The win by 27 seconds on San Francisco Bay on Tuesday cut Team NZ's lead in the first-to-nine finals to 8-7.

However, Oracle have gone ahead in wins on the water by 9-8, and would have retained the Auld Mug if not for the two-point penalty they copped pre-regatta for the cheating scandal from the 2012 lead-up series.

Team NZ have been sitting one win short of claiming sailing's biggest prize since last Thursday.

Their chance of converting their sixth match point virtually disappeared in the final moments of the pre-start, a phase where Oracle skipper James Spithill has held the upper hand over rival helmsman Dean Barker.

This time, Oracle's late aggression led to not just one, but two penalties against Team NZ.

Both were for NZL5 getting too close when required to keep clear, the boats touching on the second occasion.

While the New Zealanders were forced to wait as the time penalties elapsed, USA17 sailed away.