Ontario defeated Idaho 4-3 on Friday night at CenturyLink Arena.
Anthony Nigro, the ECHL player of the week, sent the game to overtime after knotting the score at 3-3 with a third-period goal.
Yasin Cisse scored the game-winner in the sixth round of the shootout. Ontario (3-0-2) is the only team in the Western Conference without a loss in regulation.
Forward Mitch Wahl and defenseman Patrick Cullity scored the other goals for Idaho (2-2-1), which will host the Reign again Saturday night as it plays the second game of a six-game homestand.
Idaho goalie Pat Nagle (1-1-1) stopped 31-of-34 shots before turning away 4-of-6 in the shootout. Idaho outshot Ontario 41-35.