2014 Australian Open, 2015 French Open, 2016 US Open Champion Stanislas Wawrinka used his Yonex VCORE Tour tennis racquet to win his first major tennis championship. Yonex prides themselves on being innovators in the latest tennis technologies and are commited to pushing the limits on the tennis court. The development of the Isometric head shape has allowed Yonex tennis racquets to have a sweet spot that is nearly 7% larger. From the Vcore Xi series to the EZONE Ai series used by Ana Ivanovic, Yonex is a great racquet choice to improve your game.