ble don . ▁ ▁In ▁the ▁latter ▁half ▁of ▁the ▁season , ▁Ke ys ▁strugg led ▁with ▁different ▁inj uries ▁and ▁also ▁was ▁compet ing ▁without ▁a ▁primary ▁coach . ▁She ▁did ▁not ▁attempt ▁to ▁defend ▁her ▁title ▁at ▁the ▁Sil icon ▁Valley ▁Classic , ▁withdraw ing ▁due ▁to ▁a ▁right ▁w rist ▁injury ▁before ▁the ▁start ▁of ▁the ▁event . ▁Ke ys ▁only ▁played ▁in ▁one ▁tournament ▁during ▁the ▁US ▁Open ▁Series , ▁reaching ▁the ▁quarter final s ▁at ▁the ▁C inc inn ati ▁Open . ▁During ▁the ▁event , ▁she ▁sn apped ▁a ▁five - match ▁losing ▁stre ak ▁against ▁reign ing ▁W im ble don ▁champion ▁and ▁world ▁No . ▁ 4 ▁Angel ique ▁Ker ber . ▁At ▁the ▁US ▁Open , ▁Ke ys ▁made ▁it ▁to ▁the ▁semif inals ▁while ▁dro pping ▁just ▁one ▁set . ▁However , ▁she ▁was ▁unable ▁to ▁reach ▁the ▁final ▁for ▁a ▁second ▁straight ▁year ▁after ▁losing ▁to ▁the ▁event ual ▁champion ▁Na omi ▁Os aka . ▁Ke ys ▁could ▁not ▁convert ▁any ▁of ▁her ▁th ir teen ▁break ▁points ▁during ▁the ▁match . ▁Following ▁the ▁US ▁Open , ▁Ke ys ▁played ▁in ▁three ▁tournament s ▁during ▁the ▁Asian ▁hard ▁court ▁season ▁and ▁needed ▁to ▁withdraw ▁or ▁ret ire ▁from ▁all ▁three ▁due ▁to ▁a ▁left ▁kne e ▁injury . ▁At ▁the ▁W TA ▁El ite ▁Tro phy , ▁she ▁advanced ▁out ▁of ▁her ▁round ▁ro bin ▁group ▁through ▁the ▁tie break ▁criteria ▁after ▁defe ating ▁D aria ▁Kas at k ina ▁and ▁losing