TENNIS star Peyton Stearns required medical treatment behind the scenes after having two play two matches in one day.
Stearns had been enjoying a productive week, beating Zheng and Ons Jabeur in singles and winning a round in the doubles with Sun.
Stearns had also been due to be in doubles action alongside partner Lulu Sun, with the duo scheduled to face top seeds Katerina Siniakova and Taylor Townsend.
The world No.46 withdrew from her doubles match and subsequently posted a worrying picture of herself laid out on her back in clear discomfort, receiving treatment from two paramedics.
The former NCAA champion began her eventful day by beating seventh seed Zheng Qinwen 3-6 6-4 6-4 in a gruelling two hour and 35 minute battle.
