No ........ REALLY.... think about it. There really is NOTHING that can be done about a soft "serve" underhanded. It loops over the net and hardly bounces up. Trust me....... it is effective. I just wonder if it's against the rules now.
I'm with you and I agree as to the effectiveness. I'd just like to see it one time against a real pro.
We used to play against a girl that would hit what we called the "puff serve". It would just barely clear the net and was impossible to return. You couldn't tell from her motion when she was gonna use it so it drove us crazy. If you hunched up she'd hit one hard (for her) and it was just hard enough to give you trouble.
Come to think of it, I down know if I ever won a match.
Hingis used it once in a match (maybe against one of the Williams sisters and in a fit or pique) and was roundly boo'd.
I haven't looked at the rules in awhile, but as I recall, the only requirement is that the player put the ball into the air, then, before the ball strikes the ground, to hit it with the racket so that it hits inside the service box. The rules I saw had no requirement for overhand vs. underhand.