Martina Hingis played the North American hard-court season.
Martina Hingis . In July 2013 , Hingis came out of retirement to play the North American hard-court season , partnering Daniela Hantuchová . The US Open Series is the seven-week summer tennis season linking twelve ATP World Tour and WTA Tour tournaments together . It is often referred to as the U.S. or North American hard court season .