Unsettled winds in San Francisco Bay on Saturday forced another postponement of the 34th America's Cup.
Defending champions Oracle Team USA have narrowed the gap on Team New Zealand, to keep the competition alive.
The American team won the second race on Friday to trail 8-3, with the first to nine points clinching the trophy.
New Zealand have needed only one win since Wednesday but a combination of bad weather and poor racing means they have been unable to complete the task.
"We saw this day coming a few days ago," said regatta director Iain Murray.
"We got the teams together last night to talk about the possibility of a light and variable wind from the south today.
"We do have an alternate course that we offered up to the teams, but they weren't interested in sailing that course. They preferred to wait until the wind is back to the south-west on the normal racecourse.
"The racing that's left is extremely important and the teams don't want to chance something that they're not prepared for," added Murray.
A win for Team New Zealand on Sunday would secure their third America's Cup after previous victories in 1995 and 2000, while Oracle Team USA need to win six consecutive races to retain the trophy it won in 2010, after being penalised two points by the international jury before the event began.
America's Cup schedule
Sun, 22 Sept: Race 14 (21:15), *Race 15 (22:15)
BBC coverage times
Highlights (all BST)
Sun, 22 Sept - 15:15 (BBC Two)