Faora has an exploitable weakness, her need for the krypton battle-armor/suit.
That aside, Mary's also likely stronger and faster, since she's supposed to be on par with Hancock; if not more powerful and he has the trainstopping feat and moving so fast he appeared as a blur to the bank robbers.
So Mary takes this by either damaging the facemask or just beating Faora with her greater strength and speed.
You should have made a Round Two: Scissoring Contest, who pops first