I'm not sure how much my advice is worth, but I've been on this extended weight loss thing for pretty much the past year, and I've dropped almost 40 pounds, and a ton of bodyfat (from around 22% to just over 12% now). I actually got a lot of good advice from a few bodybuilding websites, since when it comes to reshaping the body and things like that, those guys seem to have it down to a science.
Losing only a pound or two a week is the safest way to do it. If you burn more than that, you're probably burning away muscles too, which kind of defeats the purpose. I'd shoot to increase your protein intake (aim for about a gram of protein per pound of bodyweight), and try and balance out your macronutrients to a 40/40/20 scheme (40% of calories from carbs, 40% from protein, and 20% from fat). The easiest way to start losing the weight is to look up your basal metabolic rate, and figure out how many calories you're going to need to get as a minimum. A good calorie number to aim for is somewhere around 300-500 below your total calories burned (BMR+activity levels), since that will automatically create a defict that will cause you to lose fat. The higher protein content in your diet will help to prevent catabolism (muscle loss). Split the food up into 5-6 meals spread out evenly throughout the day. That will help keep your body's metabolism up and it'll prevent your body from going into starvation/storage mode.
It probably wouldn't hurt to do a bit of strength training too, since muscles are what burn up the calories you're using, and if you have more muscle, you'll burn more calories per unit time. You don't have to aim to be like Arnold or Ronnie Coleman, but just pumping some iron on a regular basis will help you along. Plus, the added strength and muscle will help augment your tennis game (more power, less chance of injury, etc.). Just so long as you have a good stretching regimen along with the strength training, you won't have to fear being muscle-bound.
I hope that this will help you out at least some. I've been following this kind of diet/work-out plan for the past 3-4 months, and it's done great things for me. I'm hoping to hit the tennis courts more when it stops raining so much over here in Hawaii and seeing what all this work on the diet and in the gym has done for my tennis. Good luck!