During Clijsters's first retirement, the invitation to participate in the roof test exhibition series at Wimbledon in May 2009 inspired her to return to the WTA Tour. In the summer, she joined the St. Louis Aces of the World Team Tennis league to help prepare for her comeback. She also participated in World Team Tennis the following year as a member of the New York Sportimes. Ten years after the roof test on Centre Court that inspired her comeback, Clijsters returned to Wimbledon to participate in an exhibition series to test the new roof on Court No. 1 in which she played a set of singles against Venus Williams as well as a set of mixed doubles.