What is the test for determining whether a jury's verdict was contrary to the evidence in a sexual assault case?

The parties agree that, in determining whether a new trial should be granted on the basis of the jury's verdict being contrary to the evidence ( 1181, subd. (6)), the trial court has the power to evaluate the weight and sufficiency of the evidence (People v. Borchers (1958) 50 Cal.2d 321, 328), as well as its credibility (People v. Veitch (1982) 128 Cal.App.3d 460, 467), and is to act effectively as a "13th juror." (People v. Lagunas (1994) 8 Cal.4th 1030, 1038.) The trial court's determination in deciding whether the verdict was contrary to the evidence rests upon a determination about whether sufficient credible evidence supports the jury's verdict. (People v. Robarge (1953) 41 Cal.2d 628, 633.)