MELBOURNE (Reuters) - Emirates Team New Zealand face a huge challenge to deny Oracle Team USA a miracle comeback in Wednesday's winner-takes-all showdown, but can still win if they forget their "scar tissue", says former America's Cup-winning skipper John Bertrand.
Oracle won two more races on Tuesday to extend their streak to seven, frustrating a sailing-mad nation of 4.5 million who thought sport's oldest trophy secured after New Zealand had earlier stormed to an 8-1 lead.
Bertrand, whose Australia II yacht ended 132 years of American dominance by winning the 1983 challenge, said New Zealand had done little wrong out on the water, but had unquestionably been trumped in the technical race.
"Oracle team USA have come on strong from a technical point of view and from a sailing point of view," Bertrand told Reuters in a phone interview.
"They've made some very, very excellent decisions over the last 10 days. They've updated and the boat's basically increasing speed.
"There is a speed differential. There's no question about it, but part of it is definitely tactics as well out on the water, make the right calls at the right time.
"The interesting thing about sport is that the slate is clean. If the Kiwis go in, learn from what they've done so far and the mistakes they've made and then just clear the brain and just get on with tomorrow's race with no scar tissue -- that's their big challenge.
"If they can do that, then they can actually still win it."
After Tuesday's victories, Oracle's Australian skipper Jimmy Spithill said his team were riding "a huge wave of momentum" which was getting "bigger and bigger".
Bertrand, 66, is well aware of the power of momentum, having steered Australia II with its famed winged keel to an emotional 4-3 victory over the Dennis Conner-skippered Liberty, after initially trailing the regatta 3-1.
Like Australia II's crew, Oracle had successfully dismissed "the consequences of winning or losing" from their minds and just got on with the next race, Bertrand said.
Bringing in British Olympic hero Ben Ainslie as tactician had also proved a masterstroke.
"With Tom Slingsby as strategist, that combination is absolutely world best," Bertrand said, referring to the Australian sailor who won gold in the laser class at London Games.
"You've got some incredible brain power combined with Jimmy Spithill, the skipper ... All of those elements come together and make it a very, very tough act for the Kiwis to beat."
The Australian connection to Oracle's challenge also includes team general manager Grant Simmer, who was technical navigator on Bertrand's 12-metre yacht in the 1983 regatta, and 24-year-old trimmer Kyle Langford, the youngest sailor in this year's America's Cup.
Despite a strong sailing tradition and success at Olympic level, Australia have not had a challenger for the Auld Mug since Kookaburra III lost the 1987 defence to Stars and Stripes in Fremantle.
"There are more Australians now competing in this America's Cup than any other nation in the world. So it's not an issue of people and technology. These projects cost $100 million," said Bertrand, who hoped the thrilling finish to this year's regatta might pique interest of Australia's mining magnates.
"They've been busy trading with China at the moment and they've not really had much reason to go beyond that.
"It's just a matter of having the right people who have that ambition, and that includes the funding behind it, and that's a serendipity requirement."
Editing by Amlan Chakraborty