The 6-foot-6 Argentine gives you the inside track to a clean winner.

By Rick Macci
Photos by Manuela Davies/Double Exposure

1. An “inside-in” forehand is when you run around your backhand and hit a forehand straight down the line. It’s a riskier shot than the inside-out forehand, which goes crosscourt, but an incredible weapon. As del Potro shows, preparation is the key. First, you must put some space between you and the ball so you can take a full swing. Step back and to your left (if you’re right-handed) before you move forward into the shot. Notice how del Potro maintains an open stance, which will allow his upper body to rotate through the shot. His elbow has some flex, and the butt cap of his racquet points at the ball. If you don’t relax your arm, you’ll muscle the ball, which often will result in an error.

2. Del Potro drops the head of his racquet so it’s below the ball. The butt cap, which was pointed at the ball in the previous photo, is now pointing slightly upward. This is so he can brush up the back of the ball and create topspin. Del Potro’s shoulders are parallel with the net, which is perfect: You need to rotate into the shot, but if you rotate past this point before contact, you may jerk the ball out to the side. While it looks like del Potro is jumping into the shot, he isn’t. The force of him pushing down into the ground combined with his rapid hip and shoulder rotation has catapulted him off the court.

3. If you think the modern windshield-wiper forehand is radically different from the traditional topspin forehand, take a close look at this photo. Yes, modern players wrap the racquet around their bodies and finish the follow-through below their shoulders, but they still extend as far as possible toward the target before finishing their swings. They swing so quickly, however, that it looks like they’re swinging across their bodies with little outward extension. Del Potro’s arm points down the line and his momentum is toward the net. His shoulders are level and his eyes remain on the ball.

4. Del Potro’s momentum has carried him into the court. His left foot is on the ground now, and it points straight at his target. So does his head as he continues to track the ball. Del Potro’s right leg kicks back and prevents him from losing his balance. Glance back at the first photo and then at this one: You’ll see that del Potro’s shoulders have rotated 180 degrees. Rotation creates power, and there’s no doubt this Argentine’s inside-in forehand is one mighty shot.

Rick Macci has coached Andy Roddick, Jennifer Capriati and Serena and Venus Williams.

Originally published in the September 2009 issue of TENNIS magazine.