The Prada Cup won't be decided for another month – but Ineos Team UK have gained a massive psychological edge on their opponents.
It wasn't just the fact that they gained a thrilling victory to gain automatic qualification to the Challenger final, but it was the way they won.
We saw the best of British.
Ineos Team UK overcame issues before the start, had to race with slightly compromised performance due to an unspecified problem with their sail alignment and trailed by the biggest margin of the race, with a 19 second deficit at the end of the third leg.
Luna Rossa held a lead of almost 300 metres at one stage and were ahead midway through the fourth leg.
But despite all that, Ineos Team UK found a way to win.
If the wounded British couldn't be beaten today, who is going to stop them now? Especially as they will have three weeks extra development time, while Luna Rossa and American Magic contest the semifinal.
It was a contest of the tightest possible margins, but the race was won by the superior crew. The British, as they have done since the start of the Prada Cup, made better decisions when it mattered.
They were also superior with their manoeuvres, while the Italians looked wobbly on some of their transitions. And Britannia were faster downwind – averaging 42 knots to 39 knots – and slightly quicker into the breeze.
The key moment on came midway through the fifth leg.
Luna Rossa held a slight advantage but elected not to cover the British as they tacked away. It was critical, as Ineos Team UK sailed into a shift, giving them a lead which they never rescinded.
There was another flashpoint just before the finish line, as the Italians protested after a tight bow-stern cross where they held right of way, but it was immediately dismissed by the umpires.
Saturday's race was a classic – the best of the regatta so far, with a staggering nine lead changes. The start was delayed by 80 minutes, as the course was reset several times before the British played a 15-minute delay card, but it was worth waiting for.
Both boats judged the time on distance start to perfection, but Luna Rossa's early advantage was negated by a couple of poor tacks. That opened the door for Ineos Team UK, who got the inside lane for a two-second advantage at the first gate.
There were several lead changes, but Luna Rossa looked well placed with a 19-second lead halfway through the race.
The Italians were still ahead at the fourth gate but couldn't put the foot on the throat and never looked completely comfortable.
A brilliant manoeuvre by Ainslie confirmed a one-second delta at the fifth gate, and the British were favourites from there.
Considering where they were a month ago, with a disastrous performance in the America's Cup World Series, it has been a stunning turnaround, something no one outside their camp could have foreseen.
There was understandable jubilation and backslapping as they crossed the line, though Ainslie was heard telling his crew "right guys, calm down" almost immediately.
Both boats then completed their mandatory 'ghost' races, before Ineos founder and chairman Sir Jim Ratcliffe joined the British crew on board for champagne celebrations.
Luna Rossa now need to regroup for the best of seven semifinal match, which starts against American Magic on 29th January.
Another race between Luna Rossa and Ineos Team UK is scheduled for Sunday, but that is yet to be confirmed.
Heading into the Cup racing?
• Give yourself plenty of time and think about catching a ferry, train or bus to watch the Cup.
• Make sure your AT HOP card is in your pocket. It's the best way to ride.
• Don't forget to scan QR codes with the NZ COVID Tracer app when on public transport and entering the America's Cup Village.
• For more ways to enjoy race day, visit at.govt.nz/americascup.