After tapping home a rebound on a shot from her twin sister and linemate Monique Lamoureux-Morando to put the U.S. 2-0 up in the second period, she won the ensuing faceoff and broke in alone on goal.
Jocelyne Lamoureux-Davidson then fooled Russian goaltender Valeria Tarakonova by faking a wrist shot before pulling the puck to her backhand and lifting it home.
The International Ice Hockey Federation said that was faster than the previous record of eight seconds set by Sweden's Carl Goran Oberg in 1960 at Squaw Valley.
(Reporting by Dan Burns, editing by Ed Osmond)