Agnieszka Radwanska made only four unforced errors in defeating Ana Ivanovic 6-2, 6-4 Sunday in the fourth round of the Australian Open. Agnieszka has not yet lost a set in 2013, entering the Open with titles in Sydney and Auckland. Radwanska provides a superb example of how to win without extraordinary physical gifts. She's neither big and powerful nor unusually quick of foot, but she is exceptionally smart; she gains quickness by anticipation, and she puts the ball out of reach through clever placement and a full variety of spins. Along with all of the usual shots, Agnieszka uses more slice forehands, topspin lobs, drop shots, and sidespin slice backhands than any of her competitors, and all of that variety makes it more difficult for her opponents to find their timing and get into a groove of hitting the kind of overpowering shots it takes to overcome her consistency and defensive skills. If you don't have the power of a Maria Sharapova or the footspeed of a Gael Monfils, you may benefit greatly from a close study of Agnieszka Radwanska.