Switzerland's Belinda Bencic questioned the quality of the court used at the WTA Finals as she became the latest player to pull out of the end-of-season championship on Saturday. Bencic retired midway through the third set of her semi-final against holder Elina Svitolina to become the fourth player to withdraw at this year's tournament, which is being played on a temporary hard court at the indoor Shenzhen Bay Sports Center. "I was cramping," said Bencic.