Marshall's trickery was a constant threat to a fragile Wednesday defence in the second half, and when he combined expertly with Madine to force a corner, Michalik was on hand to thunder in a volley from inside the penalty area.
As the match moved into injury time, another Morais free-kick was not dealt with by goalkeeper Paul Gallacher and Davidson's volley was blocked on the line by the hand of a St Mirren player.