Oracle Team USA revived their flagging hopes with an impressive display in the America's Cup on Saturday as Team New Zealand came close to calamity.
The holders won race eight by 52 seconds after the Kiwis came within inches of capsizing, to narrow the overall score to 6-0 to New Zealand.
Saturday's second race was abandoned after the start because of high winds.
New Zealand need three more wins to clinch the Cup, while Oracle need to win nine after a two-point penalty.
The American outfit, bankrolled by software billionaire Larry Ellison, have won two races but were docked two points for illegal modifications in the America's Cup warm-up series.
In San Francisco, the defending champions have been under serious pressure from the start in the face of a faster New Zealand boat upwind and slicker Kiwi crew work.
After going 4-1 behind in wins, Oracle promoted Britain's four-time Olympic champion Ben Ainslie from warm-up skipper to tactician on Thursday, and made a series of technical adjustments to the boat for Saturday's races.
The changes appeared to pay dividends in race eight as Oracle displayed impressive pace on the windward third leg to claw back the Kiwis lead from the start.
In a tight upwind battle, the decisive moment came when Team New Zealand almost tipped over after the rigid wing sail got stuck on the wrong side during a tack. As well as losing momentum, they were penalised for impeding Oracle and the Americans sailed clear to a stunning victory.
Race nine was abandoned with New Zealand leading early on leg three because the wind had exceeded the 22.6-knot limit during a five-minute period. It has now been rescheduled for Sunday.
The winners of the 162-year-old America's Cup get to decide the format and venue for the next event.