Popoff's goals came 36 seconds apart late in the second period. The second of the two was the eventual winner.
Johnny Wesley scored in the first period for Vancouver (8-11-0), while Ryely McKinstry, Brennan Menell and Matt Bellerive chimed in as well. Cody Porter made 19 saves for the win.
Parker Wotherspoon and Lucas Nickles replied for Tri-City (12-9-0). Evan Sarthou stopped 37 shots for the Americans.
Neither team scored on the power play, with the Giants going 0 for 2 and Tri-City going 0 for 1.
PATS 8 RAIDERS 3
PRINCE ALBERT, Sask. — Pavel Padakin scored twice and added two assists in Regina's rout of the Raiders.
Austin Wagner had a goal and two assists for the Pats (9-9-1), while Adam Brooks, Morgan Klimchuk, Connor Gay, Kyle Burroughs and James Hilsendager chipped in as well.
Jordan Tkatch, Sawyer Lange and Dylan Stewart supplied the offence for Prince Albert (8-12-0).
WARRIORS 6 THUNDERBIRDS 2
MOOSE JAW, Sask. — Jack Rodewald had the eventual winner and added an assist as the Warriors downed Seattle.
Kolten Olynek and Brayden Point also scored in the second period for Moose Jaw (8-10-2). Jiri Smejkal, Brett Howden and Dustin Perillat added singles.
Alexander True and Nick Holowko had goals for the Thunderbirds (8-8-3).