Sir Ben Ainslie was unable to reverse the fortunes of his struggling Oracle Team USA as the defending champions lost two more races to Emirates Team New Zealand in the America's Cup.
Britain's four-time Olympic champion was drafted in for his Cup debut but the Kiwis extended their lead to 6-1.
Oracle have won a race but were docked two points for illegal modifications and they are effectively on minus one.
The first team to nine wins will claim the 162-year-old America's Cup.
Ainslie, 36, was called up from his role as Oracle's warm-up skipper to replace veteran tactician John Kostecki, 49, on Thursday, with the under-fire holders searching for a way back into the 34th America's Cup.
But despite Ainslie's five Olympic medals, he could not compensate for Oracle's lack of pace upwind.
In Thursday's first race on San Francisco Bay, the US team - with only one American actually on board - won the start and led by 12 seconds around the second mark.
But Ainslie's crew were overhauled by the faster and slicker Kiwi outfit on the upwind leg and Dean Barker's Team New Zealand sailed away to win by 47 seconds.
In race seven, Barker's men were first at the start and extended their lead around the five legs to win by their second biggest margin of 66 seconds.
"The first start was a shocker. I was half asleep throughout that one," said Barker. "But full credit to the guys, we stuck with it and took our chance upwind.
"The second one I was conscious I had let the guys down and it all worked out pretty much as I hoped."
Team New Zealand dominated the event's first three races in the revolutionary 72ft catamarans, before Oracle hit back in race four on Sunday.
But, after a rest day, the Kiwis again impressed with their speed and boat handling to win race five by 65 seconds following a number of tactical errors by Oracle.
The Larry Ellison-bankrolled Oracle team appeared to be rattled and played their one "postponement card" of the regatta, to call off race six and "regroup".
But the Kiwis are now just three wins from reclaiming the Cup they last won in Auckland in 2000.
The winners of the event earn the right to choose the format and venue of the next America's Cup, the oldest trophy in international sport.
America's Cup schedule
Sat, 14 Sept: Race 8 (21:15), Race 9 (22:15)
Sun, 15 Sept: Race 10 (21:15), *Race 11 (22:15)
Mon, 16 Sept: *Race 12 (21:15)
Tue, 17 Sept: *Race 13 (21:15), *Race 14 (22:15)
Wed, 18 Sept: Reserve Day
Thu, 19 Sept: *Race 15 (21:15), *Race 16 (22:15)
Fri, 20 Sept: Reserve Day
Sat, 21 Sept: *Race 17 (21:15)
Sun, 22 Sept: *Reserve Day
Mon, 23 Sept: *Reserve Day
BBC coverage times
Highlights (all BST)
Fri 13 Sept - 13:30-14:15 (BBC Two)
Sun 15 Sept - 12:15-13:00 (BBC Two), 14:30-15:15 (Red Button)
Mon 16 Sept - 13:30-14:15 (BBC Two), 14:15-15:00 (Red Button)
Wed 18 Sept - 11:15-12:00 (BBC Two), 12:00-12:45 (Red Button)
Fri 20 Sept - 13:30-14:15 (BBC Two), 14:15-15:00 (Red Button)
Sun 22 Sept - 14:05-14:50 (BBC Two), 16:40-18:10 (Red Button)