Some things to try:

Pre-cut with the blade just high enough to score the bottom surface.

Put masking tape along the bottom surface to support the melamine.

Pre-score with a marking knife.

Cut 1/8 over size and use a router with a straight bit and
straightedge to do the final trim.

Also a "standard" blade isn't the right blade. Get a blade designed
for laminates, like a 80 or 100 tooth with a negative rake triple
chip.