New Zealand won the opening tournament of the men's World Rugby Sevens Series in Dubai after beating the USA 21-5 in the final.

The victory, New Zealand's first in Dubai since 2009, backed up July's World Cup win in San Fransisco. The omens for this season are good, too, as for the past three seasons the winner of the season's first tournament has also gone on to lift the overall title.

Tone Ng Shiu's try gave the Kiwis a 7-0 lead heading into halftime, but they were reduced to six men at the start of the second period and Stephen Tomasin mustered a repsonse for the USA.

Scores from Dylan Collier and Ngarohi McGarvey-Black, however, ensured New Zealand wrapped up its sixth title in Dubai.

"I'm incredibly proud of how the boys played in those last two games," said captain Scott Curry, who was one of four injured New Zealand players sidelined during the final.

"We'll take a lot out of how we played in those last two games. We were down to nine men and we were rotating our subs. The guys defended their hearts out."

New Zealand reached the final by way of wins over Wales, Spain, Scotland, England and two victories against the USA.

For the Eagles, this year's tournament was a vast improvement on the 2018 edition when they lost all five games and placed joint-last overall. A dramatic late try from Danny Barrett saw them oust Australia 22-17 in the semifinal.

England avenged a pool-stage defeat to claim the bronze medal with victory over Australia in the third-place playoff. The tournament saw star player Dan Norton become the first man ever to score 300 World Series tries.

This year has the added incentive of Olympic qualification on the line. The top four teams in the overall standings at the end of the season will all book spots at Tokyo 2020. Remaining teams will have to fight it out in continental qualifier events.

New Zealand strikes twice

Dubai proved to be a special tournament for New Zealand, which also won the women's competition to add to its victory at the season opener in Glendale, Colorado.

The Black Ferns went relatively untroubled in the later stages of the tournament, with victories over Russia (31-0), USA (22-0) and Canada (26-14).

Tries from Theresa Fitzpatrick, Gayle Broughton and a brace from Tyla Nathan-Wong were enough to see New Zealand over the line in the showpiece, preventing Canada from taking its first title since February 2017.

"I'm stoked with the win -- this tournament we really had each others' backs," said Nathan-Wong.

"It doesn't matter who's wearing that black jersey, we've got each others' backs and we really stepped it up. We stayed composed and communicated really well and we got the win.

The Dubai event also saw Black Ferns' Michaela Blyde, recently crowned World Rugby women's sevens player of the year, become the fifth player to notch 100 tries in the World Series.

The women's competition, where World Cup qualification is also up for grabs, resumes in Sydney on February 1.