But the Eagles, at full complement, couldn't expose the tired New Zealanders because they weren't able to offload, and were plagued by errors.
Matai Leuta was stripped of the ball by Knewstubb near the tryline, and New Zealand used the turnover to score at the other end, as Tone Ng Shiu powered past Ben Pinkleman.
Another U.S. chance was wasted when Pinkleman's pass off the floor to Leuta was dropped, then Perry Baker dropped a catch on the right wing to end the half.
New Zealand was reduced to six at the start of the new half when Luke Masirewa was sin-binned for a high tackle, and a Martin Iosefo break drew the Kiwis to free Stephen Tomasin to score untouched for the U.S.
But then the Eagles knocked on at the restart, Collier caught them sleeping, and to cap a comical phase, they lost possession when they had eight men on the field.
A converted try to Ngarohi McGarvey Black finished the scoring, as the New Zealand men followed their women's team from a day before in becoming champions. But the men's last Dubai title was nine years ago.
Far tougher was the semifinals, where New Zealand scored early against England, led 7-5 at halftime, then spent the entire second half on defense, as England remarkably did everything but score.
England, which beat defending champion South Africa in the quarterfinals, came from behind against Australia to finish third overall.
The U.S. knocked out Fiji in the quarterfinals and Australia in the semis.
The second leg is next weekend in Cape Town.
