Italy's America's Cup contender has recovered from a dramatic, high-speed nosedive during race seven against their British rival, bouncing back to square the challenger series at 4-4 in Barcelona.

The Italians have already suffered several problems with their AC75 boat during the long campaign to become the challenger for the 'Auld Mug', which dates back to 1851.

"These curve balls that keep coming our way ... We are sort of making a habit of this ... We are really going to learn what we can from today," Italy's co-helm, Australian Jimmy Spithill, said on the America's Cup live broadcast after Tuesday's racing finished.

INEOS Britannia, co-helmed by four-time Olympic gold medallist Ben Ainslie, won the morning race after Luna Rossa was forced to forfeit as their support team used tape to repair their 'silver bullet', finishing it just in time for the crew to make the start of the second race.

The Italians' sleek silver foiling monohull had crashed bow-first into the Mediterranean waters just as it picked up speed after bearing away from the top mark of the first leg of eight in the head-to-head race.

However, race eight started with an unforced error by the British, who skidded out of the boundary during a high-speed turn in the 'pre-start', incurring a distance penalty which they could not shake until they crossed the line, gifting Italy an early lead.

"We just got out of position," said Ainslie, with the high speeds the AC75s are sailing at meaning any slight misjudgement is accentuated.

"It was our mistake and they (Italy) did a really good job to defend," Ainslie added, describing the closely-fought contest as "two good teams really going at it hammer and tongs".

"The balance is right on a knife edge," Aisnlie said, "and of course the more races we go through it's getting more and more critical."

"The thing that I'm happy about is that every time we've had to face an issue we've actually got stronger and stronger," Spithill said of Italy's recovery.

"You are always going to face some sort of adversity at the top end and the key thing for us is we know we can deal with it," the two-time America's Cup winner added.

"We're going to carry that momentum into tomorrow and we'll get ready for the fight," Spithill said.

Both teams now need three more wins in the first-to-seven Louis Vuitton Cup, with the winners getting to challenge defenders New Zealand for the America's Cup.