Ostapenko upended by world No 569 Dayeon Back in Seoul

Local wildcard Dayeon Back came from 5-2 down in the third set and saved a match point as she stunned former French Open champion Jelena Ostapenko, the No 2 seed, 3-6, 6-1, 7-6 (4) to reach the second round of the Korean Open on Tuesday.

The world No 569, who has won two events on the ITF Tour in recent weeks, won the deciding tiebreak 7-4 to set up a clash with Australian Kimberly Birrell.

Korea Open WTA 250, other first-round results (Olympic Park Tennis Centre, hard, most recent results first):

• Kayla Day vs. Marie Bouzkova: tuesday
• Kimberly Birrell beat Sachia Vickery (Q): 6-4, 6-4
• Jessica Pegula (1) beat Viktoria Hruncakova: 6-2, 6-4
• Emina Bektas beat Laura Pigossi: 6-7 (5), 6-4, 7-5
• Su Jeong Jang beat Sofia Kenin (5): 6-1, 6-4
• Eva Lys beat Anna Karolina Schmiedlova: 6-2, 6-4
• Ashlyn Krueger beat Nadia Podoroska: 6-2, 6-4
• Kaja Juvan beat Katie Boulter (8): 6-4, 6-4
• Arantxa Rus (7) beat Na-Lae Han (WC): 6-1, 6-3
• Yue Yuan beat Arianne Hartono (Q): 6-1, 6-2
• Polina Kudermetova beat Alycia Parks (6): 3-6, 6-1, 6-0
• Ekaterina Alexandrova (3) beat Mai Hontama: 6-3, 6-1
• Kathinka von Deichmann beat Irina Khromacheva (LL): 5-7, 6-4, 3-0 ret.
• Yanina Wickmayer beat En-Shuo Liang (Q): 6-3, 6-4
• Claire Liu beat Yeonwoo Ku (Q): 6-3, 6-3