Sofya Zhuk's perseverance paid off at the Indian Wells Masters on Saturday, as she converted her 12th match point to eventually get the better of 18th seed Magdalena Rybarikova.

Russian teenager Zhuk served for the match leading 5-4 in the third set, only to be sensationally denied victory as a host of chances went begging.

Rybarikova saved match point on a remarkable 11 occasions, but was then broken to love in the next game.

Zhuk was not prepared to let another opportunity slip and proved more clinical as she again served for a place in the last 32, a gritty hold securing a 6-3 2-6 7-5 triumph after more than two and a half hours of play.