The 18th-ranked German has one of the best flat serves in the world -- Katrina Adams explains here how to replicate it. [Originally published in the March 2012 issue of TENNIS.]

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One of the WTA's rising stars, Sabine Lisicki rallied from an injury-plagued 2010 season to catapult herself to a Top 20 ranking. She became only the second player in women's tennis history to advance to the Wimbledon semifinals after having entered as a wild card and was named Comeback Player of the Year by the WTA for her outstanding season. (AP Photo/Yves Logghe)

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To hit a great serve, your body must be loose and relaxed. Lisicki starts with most of her weight on her back foot, where it needs to be when she loads up her serve. I like the extension of her tossing arm: Her elbow is locked. A straight arm makes for a smoother, pendulum tossing motion and a more accurate toss. (David Kenas/AP)

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Lisicki smoothly lifts the ball and releases it above the level of her head so that the ball has less distance to travel -- her arm is extending toward the spot where she wants the ball to go. Like most modern players, she doesn't lift her tossing arm and her racquet together. Instead, her racquet head points to the ground. She's using a Continental grip and her wrist and fingers are loose. The racquet looks as if it's dangling from her hand. (David Kenas/AP)

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Lisicki fully extends her tossing arm. It is in line with her head, which is looking up at the ball. Notice that her right wrist has some flex in it. It's still loose. Her weight has now shifted to her left foot as she begins to move her right foot forward. (David Kenas/AP)

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This is a perfect image. Both of Lisicki's knees are bent. You can't see her face, because her tossing arm remains fully extended. Her racquet is up now and her right foot has come forward, but not too far -- it's still slightly behind her left foot. Club players often bring their back foot too far forward. If it passes your front foot, you'll open up too soon and lose a lot of power. Lisicki is ready to launch herself into this serve. (David Kenas/AP)

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Here, Lisicki is off the ground -- and her racquet is down behind her back. On the serve, power goes from the ground up. She's already over the baseline and moving both up into the ball and forward into the court. Her tossing arm has dropped out of the way but her head remains up and she remains sideways. Her back has some arch, too. You'll notice that good servers point their chests up at the ball as they explode into their forward swings. (David Kenas/AP)

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Lisicki's contact is excellent. Her hitting arm is fully extended and the ball hits the upper zone of her racquet's sweet spot. She's now well over the baseline and at her highest point above the ground. She has a great shoulder-over-shoulder rotation that gives her a lot of power without a lot of strain. (David Kenas/AP)