A furious Ben Ainslie hit out at Kiwi commentator Stephen McIvor after his team went 3-0 down in the 37th America’s Cup on Sunday.

Ainslie was overheard calling the New Zealander a “f------ w-----” off camera after they had finished a live post-race interview.

There was some confusion over what exactly caused Ainslie’s outburst, which has provided some real needle in the first-to-seven series.

After a near-collision between the two boats in the pre-start, for which Britain were handed a costly penalty, New Zealand won Race 3 by 52 seconds.

Afterwards, as is customary, the live feed went to the two boats for interviews with the helmsmen.

McIvor was just coming to the end of his allotted time with Ainslie when he asked the four-time Olympic champion: “Still believe that you’re as close [to New Zealand] when it comes to performance? Because I get that feeling coming off your boat.”

Regardless of whether there was any slight intended, Ainslie appeared genuinely to feel that McIvor was questioning either his boat, or his crew’s belief.

“Maybe that’s the Kiwi commentator in you, mate” he replied. Then, as he got up, with his microphone still live, he was heard to mutter off camera: “F------ w-----.”

Asked later whether he knew his microphone was still on, he replied: “Possibly.”

“I just thought it was a bit of a stupid comment from the Kiwi commentator,” Ainslie added. “But I think it’s good for our team, you know? It’s good motivation.”

Ainslie has a history of losing his temper in competition. A shy and rather diffident character off the water, he was famous, particularly in his dinghy days, for transforming into a beast on it.

He was once disqualified from a world championships in Perth for boarding a media boat and threatening a photographer.

Most famously, at the London 2012 Games, Ainslie accused Dane Jonas-High Christensen and Dutchman Pieter-Jan Postma of “ganging up” on him by calling him for a penalty he did not deserve.

“They’ve made a big mistake,” Ainslie memorably said. “They’ve made me angry and you don’t want to make me angry.” Ainslie duly turned a difficult week into a winning one, going on to claim his fourth successive Olympic gold on home waters.

It remains to be seen whether Ineos can harness the bad blood from this incident and use it to drive them forward. The Kiwis appeared to take great delight from the fact that they forced a penalty on Ineos in the pre-start to Race 3.

Ainslie, an aggressive match racer, was expected to try to target opposite number Peter Burling in the pre-starts and Kiwi coach Ray Davies appeared almost to taunt Ainslie in his own mid-race interview.

Asked about New Zealand’s aggression in the pre-start, he said: “We’ve been practising it a lot. Ben’s been asking for someone to do it for quite some time. So it was good that it was us that gave him one of those.”

Sunday’s second race was cancelled over a lack of breeze and will now be raced on Monday, which had been scheduled as a reserve day.