It is match point in the America’s Cup. Ineos Britannia will need to beat Emirates Team New Zealand in all of the five remaining races if they are finally to win the Auld Mug for Great Britain.

After the fifth day of racing, Ineos trail 6-2 in the best-of-13 series, which means that if the New Zealanders win one more race the challenge will be over. Ineos Britannia’s skipper, Ben Ainslie, has overcome worse odds before now, but you’d be brave to back him to do it again given the manner of New Zealand’s performances in the seventh and eighth races on Friday.

“It’s still not over yet, we’ll keep fighting,” Ainslie said. “I’ve been in far too many shitfights in my career. There are many scenarios similar to this, where it might appear pretty hopeless but actually you just never know what might happen. You’ve just got to keep digging, keep fighting. We need perfection from here on in. We don’t have any second chances. And in some ways that’s easy, because you know what you have got to do.”

The momentum Ineos had built up by winning the fifth and sixth races on Wednesday sputtered out in the opening moments of the seventh race, when, as Ainslie admitted, they were beaten in the first shift. Britannia crossed the start line first, but Emirates Team New Zealand tacked right into the stronger wind down the side of the course and swept ahead into an insurmountable lead. By the start of the last leg of the race, they were almost a kilometre in front. “That was a tough race for us,” Ainslie said. “It looked like we were going to be in reasonable shape on the line, then the breeze kicked in on the right, and they did a good job of defending it.”

It didn’t help any, that, as New Zealand skipper, Pete Burling, gleefully pointed out, Ainslie erred in the prestart by tacking too early. “Yeah, in hindsight we could have tacked later and more in their wind,” Ainslie said. “But it got super light and I was actually worried we might not make the tack and make it back to the line. But hindsight is a wonderful thing. If we’d tacked two or three seconds later it would have been much harder for them.”

The conditions had changed, again. The waves were flat, the wind was offshore from the city, and came in erratic gusts, which created huge variations across the course. They are exactly the sort of conditions the New Zealanders are used to from back home.

Their boat, Taihoro, has the edge over Britannia in calm waters, and their crew, spurred on by their own anger about their sloppy performance on Wednesday, did a superb job of making it pay. Their manoeuvres were smooth, their tactics sure, and their progress steady and swift. At times they were travelling up above 47 knots.

The British were deflated by the seventh race, and defeated by the eighth, which wasn’t too much closer. They damaged their rudder somewhere along the way, apparently after colliding with an object in the water, but Ainslie refused to make an excuse of it.

“We did have a couple of moments with the rudder in the second race, but it didn’t really affect that race. The Kiwis had done a good job and were already ahead, so we’re not claiming that was an issue on the day,” he said. “Credit to the Kiwis, they sailed two brilliant races. We had good starts but we just couldn’t get that first shift off the line right. They got in front, and made us pay for it. That’s it.”

By end of the day the atmosphere on board Britannia was so quiet it felt almost funereal. Ainslie insists that there are still performance gains to wring out of the boat, but the truth is that Britannia is outmatched by Taihoro in calm water. Unfortunately for Ainslie and his team, the forecast is light for the weekend, and it’s a worry whether there will even be enough wind for them to race at all. In those conditions, it’s going to be all but impossible for him to orchestrate the kind of comeback he oversaw in 2013, when he was the tactician on the Oracle Team USA that came back from 8-1 down to win 9-8. Although since he’s Ainslie, that won’t stop him from trying.

“We’ve come on a long way through this competition, and improved a massive amount. Now we’ve just got to keep that going in different conditions tomorrow. Why not come out and get a couple of bullets on the board?” he said. “Obviously at 6-2 down we’re on the back foot, but that’s the nature of the game. We’ve fought hard to get to this point and we’re going to carry on fighting all the way. I’m confident we can keep making gains, and if we do that and we keep ourselves in the game and we can get faster each race every day, then why not go all the way?”