However three single digit races to open the day saw them start the medal race with the overall lead. Going on to place 5th in the medal race the kiwis wrapped up the regatta 22 points clear and make it 21 victories in a row.
"It is really nice to take the win," says Peter Burling.
"We'd just unpacked a new boat and spent some time setting it up, one day on the water and then it was pretty much straight into the first race."
Burling explains that the Buenos Aires venue throws up some unique challenges.
"It is a different place to sail and a really challenging place to sail. The water is close to fresh water, and there's quite a lot of mud in it. It's really hard to read the puffs - but really rewarding when you get it right."
"It was a really tricky event," he continues. "We were sailing early in the day before the sea breeze came in. You can see on the score card that everyone got it wrong at some point, we were just fortunate that we only got one wrong in the gold fleet series."
"For us this regatta was about building and learning with the main event still to come.
We're really happy with how we've been going this week, but we have some more work to do."
Racing for the 2015 49er and 49erFX World Championships get underway on Monday 16th November and runs for six days with the medal races and prize-giving planned for Saturday 21st November.
"It is a really challenging place to get it right all the time - so it's going to be tough venue to sail the World Championships."
"We'll take tomorrow off and then we will be back on the water."
In the women's fleet Alexandra Maloney and Molly Meech have wrapped up the build-up regatta in 5th overall.
New Zealand was represented by a further three crews in the men's fleet including Logan Dunning-Beck and Jack Simpson, and Isaac McHardie and Trent Rippey both members of Yachting New Zealand's Aon Fast Track Squad.