Wilson is proud to be the Official Ball of the US Open since 1979. For over 35 years, touring professionals worldwide have come to trust the performance and quality of the Wilson US Open tennis ball. With Wilson, you can expect perfection. In addition to Wilson being the Official Ball of the US Open, Wilson is the Official Ball of the Australian Open and over 45 professional tournaments worldwide. Wilson tennis balls are used in more professional tournaments (WTA and ATP Tour) than any other ball and are globally recognized and trusted for great consistent performance and superior quality.