Fiji came back in the second half looking much better and scored three more tries to all but seal their second title of the season and move to the second place in the IRB rankings with 101 points, eight points behind South Africa.
In Sunday's cup final, Fiji defeated Kenya 31-12 to close in on top spot in the standings while South Africa saw off the usa 29-7 in the bronze medal game to be eight points clear at the top with four rounds remaining.
The All Blacks Sevens will play Argentina for seventh at the Vancouver leg of the world series.
"I'm speechless, really proud of the boys", Fiji captain Jerry Tuwai said. "We are a very young side and winning here in Vancouver gives us something to fight for in the rest of the season".
Kenya opened the scoring after two minutes with a try to Willy Ambaka, the 99th of his World Series career.
Sevuloni Mocenacagi scored two tries, the second of which launched Fiji's second-half surge. Kenya ended United States hopes of building on their victory last weekend in Las Vegas with a dramatic 24-19 semi-final victory over the Eagles.
NCAA reveals final 8 teams considered for women's tourney
While this may be a wide-open tournament, it may be quite hard for anyone to get the best of head coach Tony Bennett's team. On the flip side, other ESPN analysts have said they think Tim Miles' squad still has a chance to get in.
Kenya had reached the semis with a 12-0 quarter-final win over England, their first over that side since 2011.
During the semifinal, U.S. had the best of starts with Terry Baker who is enjoying in sensational form handing them two quick tries and successful conversions for a 14-0 lead in the fourth minute.
South Africa lead by 109.
They lost 24-19 to championship leaders South Africa in Sunday's quarter-finals.
The next tournament beings in Hong Kong on April 6.