Netherlands' Kiki Bertens returns the ball to 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 returns the ball to 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 returns the ball to 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 returns the ball to 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 returns the ball to 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 returns the ball to 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 returns the ball to 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 returns the ball to 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)