New Zealand beat Britain again to take 3-0 America's Cup lead

New Zealand won the third America's Cup race against Britain on Sunday to take a 3-0 lead in the first-to-seven series, after a near collision between the two before the start.

Ben Ainslie's British team were penalised after failing to keep clear in response to an aggressive close-quarters manoeuvre by Peter Burling's New Zealand crew in the pre-start.

"It was a little bit uncomfortable .. with how close the boats got," Burling said laughing on the America's Cup live broadcast immediately after the end of the race off Barcelona.

Burling said the New Zealand team had been "working on little bits and pieces" in preparing to defend the America's Cup against Britain, which won the right to challenge them.

The 33-year-old Kiwi skipper said it was "great to finally execute it in a race ... and to make it count".

Britain had to drop 75 metres behind the Kiwis after crossing the line to shake off the penalty, handing the America's Cup holders an early advantage.

"It was obviously a port-starboard and we thought we were keeping clear but the umpires didn't see it that way," Ainslie said of the decision to impose a penalty on the British, who were the give-way boat under the rules of racing in sailing.

Despite coming close to overtaking during an early tacking duel, the British were unable to get past and the New Zealanders sailed away from them for a convincing win at the finish.

"Just got to keep upbeat," said Ainslie, adding that there was a "long way to go" in the competition which Britain has never won in the 173-year history of the "Auld Mug" and has not challenged for in 60 years.

We've just got to keep pushing hard," Ainslie said ahead of the second race of the day, which is due later on Sunday.