MASON, Ohio — Before this summer, Kiki Bertens was perhaps the closest thing modern women’s tennis had to a clay-court specialist.
She had won five WTA titles, all on clay, the most recent this April in Charleston, S.C. The biggest final of her career was on the clay of Madrid. Her best Grand Slam result was a run to the semifinals of the 2016 French Open, where she lost a close two-set battle to Serena Williams.
Away from her preferred dirt, Bertens had an 0-11 record against top-10 players and had not reached the final of any grass or hardcourt tournament.