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Now that she has completed a career Grand Slam, tennis champion Maria Sharapova should be known by most of her fellow players to be fairly handy with a tennis racquet - but the Serbian tennis star Novak Djokovic may now disagree.

While reportedly filming a spot for Head, the sports equipment and clothing company, Sharapova was trying to hit a pack of tennis balls balanced on the head of the world No. 2-ranked men's player.

Sharapova managed to get the package of balls off of Djokovic's head all right, but she was about three feet south with her aim. In the video, she hits him in what appears to be the groin.

Once Sharapova makes her indirect shot, Djokovic is seen doubled over, while Sharapova can't contain herself and doubles over as well, laughing.

Whether this is an attempt to create a viral video, some on-court goofing around between two of the world's top tennis pros, or a legitimate emergency for the Serb isn't completely clear. Either way, Djokovic may want to keep a closer eye on Sharapova's famous serve.

Watch the clip of the accident here

In London for the 2012 Olympics, Sharapova has just reached the tournament's third round. If she takes the gold, she will have completed a career "Golden Slam."

Djokovic, who was seen waving Serbia's flag at Friday's opening ceremony, beat American Andy Roddick with a final score if 6-2, 6-1 and also got to the tournament's third round.