New Zealand closed in on another America’s Cup success after winning both races on Friday to move 6-2 ahead of Great Britain in the first-to-seven series.

After Ineos Britannia had won twice on Wednesday to close the gap back down to two points, Emirates Team New Zealand reasserted their grip on the Auld Mug, reading the testing conditions off the Barcelona coast perfectly to sail clear in both races.

Despite some issues with the rudder, Sir Ben Ainslie offered no excuses for coming up second best, but vowed to fight on as Britain’s hopes of a first America’s Cup suffered a severe blow.

It had been a promising start by Ineos Britannia to race seven, but the New Zealand crew soon took advantage of the rapidly shifting breeze to move out on the right and forged into a big lead.

Despite the choppy conditions, New Zealand continued to control the race, the defenders expertly protecting their position.

By the fifth leg, the advantage was up to more than 800 metres, which further increased as New Zealand eventually crossed one minute and 13 seconds clear.

Although the conditions calmed somewhat by the start of race eight, it followed a similar pattern.

This time it was the British boat – having qualified for the showpiece event for the first time since 1964 – who opted to move out right, but again New Zealand soon recovered to move clear heading towards the end of the first leg.

After Ineos Britannia dropped further back following the turn, with chat over the team’s comms suggesting a possible problem with the rudder, New Zealand took full advantage to win again, this time by more than 1000m.

“It wasn’t a good day for us,” Ainslie said in his post-race interview from on board Ineos Britannia.

“Hats off to the Kiwis, they sailed two really strong races in that shifty stuff and just managed to pick the right side off both start lines to get that first shift.

“They did a really good job of defending when they went ahead and put us in bad spots, so we have to take that on the chin, but it is still not over yet, so we will keep fighting.”

Ainslie added: “We had a little bit of an issue, but to be honest I think it really came down to the first shifts off those starts in both races and whichever boat got ahead.

“They did a really good job of defending so we will come back tomorrow – and tomorrow is another day.”

After producing a fine response from Wednesday’s double disappointment, New Zealand skipper Pete Burling paid tribute to the efforts of his crew.

“It was nice to bounce back from a few small mistakes the other day and put a couple of solid races on the board,” he said.

“The pedal teams behind me – on both sides of the boat – put in a huge stint.”

Despite now needing just one more point to wrap up a third straight America’s Cup triumph, which could come as early as Saturday, New Zealand co-helm Nathan Outteridge warned against complacency.

“I am feeling like it is not done until it is done, so looking forward to seeing you on the weekend,” he said.