The top four teams at the end of the season earn automatic qualification for the 2020 Tokyo Olympics.
After four consecutive runnerup finishes in Dubai, Cape Town, Hamilton and Sydney, the United States reached the top of the podium on Sunday in Las Vegas with a 27-0 win over Samoa in the final.
The battle for Olympic qualification continues this weekend in Vancouver, with the Eagles looking to extend their run of podium finishes to six events.
(Reporting by Steve Keating in Toronto; Editing by Hugh Lawson)