Croatian representative Antonia Ružić (WTA - 91.) has advanced to the quarter-finals of the WTA 250 hard-court tournament in Osaka. She secured her place after American Kayla Day (WTA - 119.) retired following the conclusion of the first set.
The first set went to the Croatian player 6-4. Ružić started the match against Day excellently, taking the first three games and then leading 4-1. Day recovered the 'break' deficit in the seventh game and then levelled at 4-4, saving two 'break' points in the process. Ružić held her serve to lead 5-4 and then capitalised on her opponent's errors to reach 0-40, converting the third set point after another miss from her rival.
After losing her serve in the final game of the first set, Day requested medical assistance for pain in her lower back. Treatment did not provide the desired relief, and the 27-year-old American tearfully extended her hand to Ružić.
Ružić will fight for a place in the semi-finals on Friday against eighth seed Briton Katie Boulter (WTA - 58.). It will be their first meeting. The match is scheduled as the last in Friday's programme, which begins at 4.30 am Central European Time.
