It was a fitting send-off for retiring captain Todd Clever, who was playing his record-extending 76th cap since 2003, and coach John Mitchell, who was leaving to coach South African Super Rugby side the Bulls.
The Americans' reward was a place in World Cup Pool C in Japan with England, France, Argentina, and a yet-to-be-determined Oceania side. Canada, which has played in every World Cup, will meet Uruguay in January for a slot in Pool D with Australia, Wales, Georgia and another Oceania side.
The Canadians were handicapped by the withdrawal of backs DTH van der Merwe, who scored two tries last week, Taylor Paris and Phil Mack, and were down 12-0 in almost even time, after a couple of tries by US No. 8 Cam Dolan.
Dolan also set up their third try for lock Nate Brakeley, as they led 19-3 after the first quarter.
But the Americans lost their cool and Canada rallied, with goalkicks by Gordon McRorie and 10 points while Eagles flanker Tony Lamborn was in the sin-bin.
But then Canada's discipline dropped away, and the Americans pounced.
United States 52 (Cam Dolan 2, Joe Taufete'e 2, Nate Brakeley, Nate Augspurger, Dino Waldren, David Tameilau tries; AJ MacGinty 6 conversions) Canada 16 (Admir Cevjanovic try; Gordon McRorie conversion, 3 penalties)
HT: 19-9