JACOB Birtwhistle again showed he was the best junior triathlete in Australasia with a narrow win in New Zealand at the weekend.

Victory over arch rival Luke Willian confirmed Birtwhistle as the winner of the Australian junior triathlon series and the OTU Oceania junior title for 2013.

The 18-year-old Launceston  athlete beat Willian by three seconds to win in Wellington continuing a breakout season.

 ?In the past three months, Birtwhistle has taken out the super sprint held at Runaway Bay, won a gold medal at the Australian Youth Olympic Festival in Penrith, showed his class on home soil to win the Australian junior championship in Devonport and now the Wellington triathlon to take the Oceania junior title.

In Wellington he also combined  with Joel Tobin-White, Ben Anderson and Nick McQuire in a composite Tasmania-Victoria team to win the trans-Tasman teams challenge.

 ?Birtwhistle is the first Tasmanian to have won the Australian junior points series, the Oceania junior championship and the national junior title since the awards began in 2007.

But he won't get to rest on his laurels as later this week he heads to Poland to compete in the world cross-country championships.

He is one of six juniors in the 19-man Australian team and his 8000-metre race will be held in Bydgoszcz on Sunday week.

Birtwhistle is expected to be overseas again later in the year as he is  ?considered a certainty to be selected in Australia's team for the world junior triathlon championships in London in September.

Triathlon Australia's national manager of athlete development, Craig Redman, said Birtwhistle had enjoyed an outstanding season and was part of exceptional group of junior triathletes.

``Looking at the talent we have unearthed, Australia will field some very talented teams at the world championships,'' he said.