While he now sits atop the leader board, the Wellington local is well aware that there is plenty of racing yet to come.
"I am in the lead for now, but we are only four races in, and another six to go before the medal race. We'll see how it all stands then," he says.
Meanwhile, Vujasinovic had a mid-fleet finish in 44th and is relegated to fifth overall. All scores are counted until the discard comes into play after race five.
This opened the door for Zsombor Berecz, from Hungary to move into send overall. He is currently nine points behind Junior, while Pieter Jan Postma, from the Netherlands is now in third.
Andrew Murdoch has slipped to 19th overall after placing 40th on the water today. After race five he can drop his worst result, and he will be aiming to deliver consistent top place finishes to climb back through the ranks.
John Cutler, Olympic bronze medallist in the Finn at Seoul 1988, is coach to the New Zealand Sailing Team Finn squad.
In five months, on 9 August 2016, racing at the Rio 2016 Olympic Sailing Regatta gets underway on Guanabara Bay, Rio de Janeiro.
The battle for the only Finn spot for New Zealand is likely to be one of the toughest decisions selectors will face.