Needing to pull the button for the win, Perret’s last throw curved slightly to give Canada the flight.
Einarson had forced an extra volley by making a remarkable quadruple withdrawal to clear the four-foot ring and recover a single point.
Canada trailed 5-1 after four ends, but scored three runs in the fifth and stole a single in the sixth to tie the game.
Norwegians Kristin Skaslien and Magnus Nedregotten beat Italians Stefania Constantini and Amos Mosaner 7-5 in the other qualifying match.
Canada next face Bruce Mouat and host Jennifer Dodds of Scotland later Saturday at Curl Aberdeen facilities.
Norway will face Swedes Oskar Eriksson and Almida de Val in the other semi-final.
The winners of the semi-finals will play for gold on Sunday while the losing teams will meet for bronze.
Gushue of St. John’s, NL, and Einarson of Camp Morton, Man., Finished the round robin with a 7-2 record. They are trying to become the first Canadian team to win gold in their 13-year history.
Canada has been on the podium (two silver, one bronze) in the last three editions of the competition.
Joanne Courtney and Reid Carruthers won silver in 2017, Laura Walker and Kirk Muyres won bronze in 2018 and Jocelyn Peterman and Brett Gallant won silver in 2019. Last year’s championship was canceled due to of the COVID-19 pandemic.
The 2021 event serves as the main qualifier for mixed doubles at the Beijing Olympics. Gushue and Einarson secured an Olympic berth for Canada on Friday.
Canada’s John Morris and Kaitlyn Lawes won gold when the discipline made its Olympic debut at the Pyeongchang 2018 Games.
This report by The Canadian Press was first published on May 22, 2021.