Maria Sharapova Golden Girl in US Open Tennis 2011

Still in her Nike practice gear with her ponytail swinging and her forehead faintly perspiring, Maria Sharapova would have been tough to miss recently in a quiet Toronto hotel, even if she hadn’t introduced herself. Minutes after politely excusing herself for a quick change, the striking 24-year-old reappeared in a designer-without-trying-too-hard look.

It all may appear to come easily to Sharapova, but her cool demeanor on court and in public masks an industrious work ethic and competitive fire that are evidenced by her status as the world’s highest paid female athlete. Whether slamming serves on the court, poring over sales reports for her Nike-designed line or tidying up before the cleaning woman’s arrival, the tennis champ is not one to leave anything to chance. She certainly has had plenty of practice, beyond the four hours she trains each day with racquet in hand and another hour in the gym. Sharapova was only 11 when Nike first signed an endorsement deal with her. Last year the activewear giant upped its commitment considerably with a reported $70 million deal with Sharapova that extends through 2018.