The anticipated battle between the boats of Australian Olympic gold medallists Tom Slingsby and Nathan Outteridge eventuated on day one of the inaugural SailGP event on Sydney Harbour on Friday.
Japan, skippered by Outteridge, won the opening race and also recorded two second placings.
Skippered by Slingsby, Australia finished fourth out of six in the first race on Friday before winning the last two.
Japan lead on 28 points from Australia 27, Great Britain 22, United States 20, and China and France, both 19.
The top two pointscorers after Saturday's two fleet races will square off in the final late that afternoon.
While the wind rarely got above ten knots, boat speeds edged above thirty knots, well short of the magic 50 mark they can bomb along in heavy breeze.
Slingsby said he was angry after the first race because of bad boat handling and mistakes.
"We had a list of things to go through," Slingsby said.
"We got better starts, got away from the pack and when we salied by ourselves it's pretty obvious we're fast.
"We know how good they (Japan) are, he (Outteridge) is strong but, we've shown if we do things right, if we sail the way we know we can, it's not up to if Nathan can beat us.....if we sail well, we'll win the regatta."
Outteridge said his team performed really well given it was the first race they had ever contested together.
They were penalised in race two for breaking the line prematurely and Outteridge said they needed to work on their starts.
While Australia won the last two races in strong fashion, Outteridge said the home boat was easily beatable.
"They beat us today because we made mistakes and they will probably say they lost that first race because they made mistakes," Outteridge said.
"If we both sail around the track without making mistakes it's going to be a very tight contest.
There were a couple of near misses and dramatic moments in the first race, with China and Japan coming perilously close and Great Briitan slapped with a right of way penalty after getting close to France .
The first race also produced the most bizarre moment of the day with France going around not through the finish, line after not listening closely enough to the race committee.
"We were confused on the approach to the finish line and that's why we make a big mistake," France skipper Billy Besson said.
Australian Associated Press
