Netherlands' Kiki Bertens (R) shakes hands with Romania's Simona Halep after winning their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)

Netherlands' Kiki Bertens celebrates after defeating Romania's Simona Halep during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)

Netherlands' Kiki Bertens celebrates after defeating Romania's Simona Halep during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)

Netherlands' Kiki Bertens celebrates after defeating Romania's Simona Halep during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)

Netherlands' Kiki Bertens celebrates after defeating Romania's Simona Halep during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)

Netherlands' Kiki Bertens celebrates after defeating Romania's Simona Halep during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)

Romania's Simona Halep reacts in front of Netherlands' Kiki Bertens during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by OSCAR DEL POZO / AFP via Getty Images)

Romania's Simona Halep reacts in front of Netherlands' Kiki Bertens during their WTA Madrid Open final tennis match at the Caja Magica in Madrid on May 11, 2019. (Photo by JAVIER SORIANO / AFP via Getty Images)