Both Team New Zealand and America's Cup holders Oracle claim they've gone faster than the Kiwis' course record of more than 87 km/h set in San Francisco today.
In winds on the upper limit for racing at 23 knots, skipper Dean Barker got Aotearoa to 47.18 knots (87.377km/h) to beat Luna Rossa and take a 6-1 lead in the Louis Vuitton Cup final.
New Zealand are a win away from earning the right to meet Oracle for the America's Cup next month.
Barker was thrilled with the performance of the boat today in testing conditions.
"It's really exciting. You can't help but get a buzz from it," Barker said of the new record on the race track. The previous best was 44.15 knots.
"You don't focus too much on the speedometer because you know you're going fast. There are just different types of vibrations going on, going through different speeds. You definitely know when it's really ripping because the thing feels like it's going to shake itself to pieces."
He then confirmed they'd gone faster in training.
"It's always pretty cool to hear when you've achieved good speeds. But the boat's been a lot faster," Barker said.
Kiwi bowman Adam Beashel suggested 50 knots could be possible.
The wind limit for the America's Cup will be raised a further five knots.
Oracle were quick to get in their view on today's effort by Team New Zealand.
Oracle tactician Darren Bundock told Associated Press that they had also reached a higher speed in training during their two-boat in-house testing.
He maintained that programme would serve them well for the America's Cup match.
"I think they're going to be really good competition for us," Bundock said of Team New Zealand.
"I think come the actual America's Cup, it will probably be the best racing we've seen."
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