New Zealand narrowly avoided a historic tournament upset on Sunday, overcoming a halftime deficit to defeat a determined Fiji side 18-12 in their opening match of the Women's World Cup.

The Ferns entered the fixture in Newcastle as heavy favorites. As one of the most decorated programs in the history of the sport, they share the record for the most world titles with three and have advanced to every tournament final since the competition began. However, Sunday's performance proved far more challenging than anticipated.

New Zealand initially appeared poised for a straightforward victory when Stacey Waaka crossed the try line just two minutes into the contest. Fiji quickly regrouped, however, and began challenging their more experienced opponents.

Midway through the first half, Fijian captain Sereana Naitokatoka executed a sharp dummy-half run that set up Losana Lutu for the nation's first-ever Women's World Cup try. Sienna Laing added another score shortly afterward, stunning the crowd and giving Fiji a 12-4 advantage.

Waaka managed to narrow the gap with her second try just before the break, but New Zealand still trailed 12-10 at halftime. The score marked the first time the powerhouse squad has ever found itself behind at the interval in a World Cup fixture.

Fiji maintained its resilient defensive stance well into the second half, frustrating the tournament contenders. New Zealand eventually regained the lead through a pair of penalty kicks by Zehara Temara. The victory was finally sealed in the closing minutes when a cross-field kick from Raecene McGregor allowed Leianne Tufuga to touch down.

New Zealand coach Ricky Henry admitted his team strayed from its game plan and was fortunate to escape with the win. Senior player Georgia Hale acknowledged that the squad played with uncharacteristic indiscipline, noting that Fiji capitalized on an absence of early pressure.

New Zealand will look to clean up its performance when it hosts France in Christchurch for its next Group B fixture. Fiji, meanwhile, is scheduled to play Papua New Guinea.

In the men's tournament on the same day, Fiji enjoyed a much more comfortable outing in Newcastle, defeating the Cook Islands 40-12. Solomone Saukuru starred with a pair of tries as the men's team rattled off 34 unanswered points before conceding two late scores.

The strong start provides a much-needed boost for the Fijian men's side following a turbulent preparation period that included a coaching change and administrative challenges. Head coach Mick Potter now turns his attention toward a daunting upcoming matchup against reigning champions Australia, viewing the fixture as an opportunity to secure a major tournament upset.

Reporting based on coverage first published by BBC Sport. Read the original report at BBC Sport.