When the verdict of a jury in a civil action is set aside by a trial court upon the ground that it is contrary to the evidence, or without evidence to support it, a new trial shall not be granted if there is sufficient evidence before the court to enable it to decide the case upon its merits, but such final judgment shall be entered as to the court shall seem right and proper. If necessary to assess damages which have not been assessed, the court may empanel a jury at its bar to make such assessment, and then enter such final judgment.
Nothing in this section contained shall be construed to give to trial courts any greater power over verdicts than they now have under existing rules of procedure, nor to impair the right to move for a new trial on the ground of after-discovered evidence.