Oracle Team USA cruised to an 1min 24sec win over Team New Zealand in light airs on San Francisco Bay, leaving the Kiwis still stranded on eight wins in the best-of-17 series.
Winds at both ends of the spectrum are conspiring to frustrate Team NZ as they hunt a decisive ninth America's Cup victory.
After three days of postponements due to high winds, light winds forced Saturday's first encounter to be abandoned as Team NZ sailed unchallenged toward the finish.
The 40-minute time limit expired with the Kiwis leading by more than 1000m and with little more than one nautical mile to go.
In the second race of the day, Team NZ won a rare start in 12 knot winds, rounding mark one 3sec ahead of Oracle.
But they were penalised soon after for crossing too close in front when Oracle had right of way, forcing the Americans into evasive action.
Oracle went on to extend their lead at every mark to wrap up a rare win.
Kiwi skipper Dean Barker was philosophical at the end of frustrating day's sailing.
"It was a very frustrating day, to be honest," he said.
"I think we sailed a pretty solid first race - it was disappointing to be that close yet so far away."
Oracle's superior speed downwind put them in a good position to capitalise on Team NZ's crucial error early in the re-run, but Barker says his crew haven't lost confidence.
"We know we're sailing well enough - that one came down to a few metres right at the bottom and unfortunately that was the difference."
Despite the frustration of the first race abandonment followed by a decisive loss, Barker said there was no doubt in his mind that they could wrap up the America's Cup on Sunday (NZT).
"The guys are very positive - we know we can win this thing, we just have to put it together on the day."
Skipper Jimmy Spithill said a "great call" at the bottom gate had set up Oracle's win.
"Sometimes a couple of things go your way, and you've got to take those things. It was a fantastic second race."
