Tabak was the girl who served underarm to Laura Robson in the juniors wasn't she? She tried every trick in the book that day as I recall. Needed a toilet break after the first set, called for the trainer complaining of cramp after about 45 minutes and finally resorted to an underarm serve. Pathetic. Still got thrashed by a 14 year-old.
All of the other things may have been gamesmanship, but there's nothing wrong with using an underarm serve to try to get a free point. It's no different to having a gigantic unreturnable overarm serve, like John Isner. And at one time, overarm serving was considering unsportsmanlike and unfair.
I remember when the crowd booed Hingis at the French for serving a couple of drop shots to Steffi, in the 99 final. There were quite a few things that Martina did that day, where she deserved being booed... but the underarm serving wasn't one of those things. It's perfectly legal and is simple a mix-up tactic, just like hitting a drop shot instead of a groundstroke. If players aren't prepared for such a shot and stand too far back to reach it, it's their problem.
There's very little advantage to serving underarm when the opponent is prepared for it, unless you're super-talented and can create some Bahrami-like spin. Or even better, deliberately fluff an overarm serve and hit a backhand drop shot when the ball is falling back down.
That man is a genius. I'd love to see a female player adopt crazy tactics like that. But the idea that underarm serving is somehow "underhanded" (groan), is just daft.
One of the reasons I like Marion so much is that she doesn't follow the tennis text book. As long as it's within the rules, there is no reason why you shouldn't be unorthodox if you can make it work. Obviously I am talking about things like her service motions (most aces in 2011, like somebody mentioned on her forum, so try laughing at that!
) I know she has made questionable use of medical time outs, and I've never supported that, if it has indeed been gamesmanship.
BTW, try underarm serving against Marion, and she'll whack it past you for a winner, because she'll probably be doing her own unorthodox tactic of standing by the service line to receive.
Somewhere on youtube, there is a classic clip of a really big server... Ljubicic I think... throwing in a underarm drop serve for fun. If you have a serve like his, people like to stand so far back that it's a pretty sensible tactic. If it wasn't for the fact that just serving another unreturnable bomb is easier, big servers might want to do that. The men should definitely do it against the Federers of the world, who have no trouble just blocking their serves back. Although I'll regret saying that if they read this, because Fed is my fav.