Australia's two-time winner Jimmy Spithill believes that he has raced his last America's Cup after his Italian boat, Luna Rossa Prada Pirelli, was beaten in the challengers' final by Britain's INEOS Britannia.

"I really think I am at the end of the line now. I think this is it for me," the 45-year-old Spithill said, while lauding all the young sailing talents coming up behind him.

This was his eighth consecutive America's Cup and third with Luna Rossa, but the Elvina Bay great Spithill reckoned it was the end of his distinguished America's Cup career after Luna Rossa fell 7-4 to INEOS Britannia in the Louis Vuitton challengers final.

Spithill is best known for twice winning the America's Cup with Oracle Team USA in 2010 and 2013.

That included leading an epic comeback in 2013 when the American-based crew were down 8-1 at match point before winning eight straight races against New Zealand.

Spithill was in his second campaign with co-helmsman Francesco Bruni. In 2021 in Auckland, they had steered Luna Rossa into the final where they fell to the Kiwis.

But it proved an historic day for British sailing as Ben Ainslie's INEOS Britannia became their first boat to reach the final for 60 years, setting up a head-to-head against holders New Zealand later this month in Barcelona.

There were screams and shouts of celebration among the eight sailors on board after they crossed the finish line.

The British have never won the "Auld Mug" since it began off the south coast of England in 1851 and have not qualified for the "match" to challenge for it since 1964.

But Olympic great Ainslie, the skipper, with the backing of British billionaire Jim Ratcliffe, has built a boat with the help of Formula One team Mercedes that he hopes can go all the way.

"It's a massive day for our team," Ainslie said.

"Ten years of hard work to get to this point .. it's a big moment for British sailing that's for sure."

Ainslie and his crew were joined by Ratcliffe after they were presented with the silverware for beating the Italian team in a tightly-contested race.

The 47-year-old Ainslie has made it his mission to bring the Cup home, spearheading a campaign that has cost more than 100 million pounds ($A193 million) ($A193 million) to develop a state-of-the art boat.

"There's a huge investment of time and money and you just want to make it count," Ainslie said.

The British crew, who on Wednesday broke a stalemate in the first-to-seven series with back-to-back wins, led from the start of Friday's crucial high-speed contest, holding off repeated challenges from the Italians in perfect sailing conditions.

"It's tough, but that's sport and it's going to be a tough few days for the team, but the better team won and I just want to say 'well done' to Ben and Dylan (Fletcher) and the whole (British) team," said Spithill.

Ainslie's boat was towed back to its port base to the sound of blaring horns, flanked by a flotilla of yachts and launches, with the crew gathered on deck as they savoured the moment.

The first-to-seven America's Cup match between New Zealand and Britain will begin on October 12.